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Broad-Spectrum Activity Of Membranolytic Cationic Macrocyclic Peptides Against Multi-Drug Resistant Bacteria And Fungi, Sandeep Lohan, Anastasia G. Konshina, Rakesh K. Tiwari, Roman G. Efremov, Innokentiy Maslennikov, Keykavous Parang Apr 2024

Broad-Spectrum Activity Of Membranolytic Cationic Macrocyclic Peptides Against Multi-Drug Resistant Bacteria And Fungi, Sandeep Lohan, Anastasia G. Konshina, Rakesh K. Tiwari, Roman G. Efremov, Innokentiy Maslennikov, Keykavous Parang

Pharmacy Faculty Articles and Research

The emergence of multidrug-resistant (MDR) strains causes severe problems in the treatment of microbial infections owing to limited treatment options. Antimicrobial peptides (AMPs) are drawing considerable attention as promising antibiotic alternative candidates to combat MDR bacterial and fungal infections. Herein, we present a series of small amphiphilic membrane-active cyclic peptides composed, in part, of various nongenetically encoded hydrophilic and hydrophobic amino acids. Notably, lead cyclic peptides 3b and 4b showed broad-spectrum activity against drug-resistant Gram-positive (MIC = 1.5–6.2 µg/mL) and Gram-negative (MIC = 12.5–25 µg/mL) bacteria, and fungi (MIC = 3.1–12.5 µg/mL). Furthermore, lead peptides displayed substantial antibiofilm action comparable …


Structural Analysis And Activity Correlation Of Amphiphilic Cyclic Antimicrobial Peptides Derived From The [W4R4] Scaffold, Shaima Ahmed El-Mowafi, Anastasia G. Konshina, Eman H. M. Mohammed, Nikolay A. Krylov, Roman G. Efremov, Keykavous Parang Dec 2023

Structural Analysis And Activity Correlation Of Amphiphilic Cyclic Antimicrobial Peptides Derived From The [W4R4] Scaffold, Shaima Ahmed El-Mowafi, Anastasia G. Konshina, Eman H. M. Mohammed, Nikolay A. Krylov, Roman G. Efremov, Keykavous Parang

Pharmacy Faculty Articles and Research

In our ongoing quest to design effective antimicrobial peptides (AMPs), this study aimed to elucidate the mechanisms governing cyclic amphiphilic AMPs and their interactions with membranes. The objective was to discern the nature of these interactions and understand how peptide sequence and structure influence antimicrobial activity. We introduced modifications into the established cyclic AMP peptide, [W4R4], incorporating an extra aromatic hydrophobic residue (W), a positively charged residue (R), or the unique 2,5-diketopiperazine (DKP). This study systematically explored the structure–activity relationships (SARs) of a series of cyclic peptides derived from the [W4R4] scaffold, …


Comparative Analysis Of Conformational Dynamics And Systematic Characterization Of Cryptic Pockets In The Sars-Cov-2 Omicron Ba.2, Ba.2.75 And Xbb.1 Spike Complexes With The Ace2 Host Receptor: Confluence Of Binding And Structural Plasticity In Mediating Networks Of Conserved Allosteric Sites, Mohammed Alshahrani, Grace Gupta, Sian Xiao, Peng Tao, Gennady M. Verkhivker Oct 2023

Comparative Analysis Of Conformational Dynamics And Systematic Characterization Of Cryptic Pockets In The Sars-Cov-2 Omicron Ba.2, Ba.2.75 And Xbb.1 Spike Complexes With The Ace2 Host Receptor: Confluence Of Binding And Structural Plasticity In Mediating Networks Of Conserved Allosteric Sites, Mohammed Alshahrani, Grace Gupta, Sian Xiao, Peng Tao, Gennady M. Verkhivker

Mathematics, Physics, and Computer Science Faculty Articles and Research

In the current study, we explore coarse-grained simulations and atomistic molecular dynamics together with binding energetics scanning and cryptic pocket detection in a comparative examination of conformational landscapes and systematic characterization of allosteric binding sites in the SARS-CoV-2 Omicron BA.2, BA.2.75 and XBB.1 spike full-length trimer complexes with the host receptor ACE2. Microsecond simulations, Markov state models and mutational scanning of binding energies of the SARS-CoV-2 BA.2 and BA.2.75 receptor binding domain complexes revealed the increased thermodynamic stabilization of the BA.2.75 variant and significant dynamic differences between these Omicron variants. Molecular simulations of the SARS-CoV-2 Omicron spike full-length trimer complexes …


Exploring Conformational Landscapes And Cryptic Binding Pockets In Distinct Functional States Of The Sars-Cov-2 Omicron Ba.1 And Ba.2 Trimers: Mutation-Induced Modulation Of Protein Dynamics And Network-Guided Prediction Of Variant-Specific Allosteric Binding Sites, Gennady M. Verkhivker, Mohammed Alshahrani, Grace Gupta Sep 2023

Exploring Conformational Landscapes And Cryptic Binding Pockets In Distinct Functional States Of The Sars-Cov-2 Omicron Ba.1 And Ba.2 Trimers: Mutation-Induced Modulation Of Protein Dynamics And Network-Guided Prediction Of Variant-Specific Allosteric Binding Sites, Gennady M. Verkhivker, Mohammed Alshahrani, Grace Gupta

Mathematics, Physics, and Computer Science Faculty Articles and Research

A significant body of experimental structures of SARS-CoV-2 spike trimers for the BA.1 and BA.2 variants revealed a considerable plasticity of the spike protein and the emergence of druggable binding pockets. Understanding the interplay of conformational dynamics changes induced by the Omicron variants and the identification of cryptic dynamic binding pockets in the S protein is of paramount importance as exploring broad-spectrum antiviral agents to combat the emerging variants is imperative. In the current study, we explore conformational landscapes and characterize the universe of binding pockets in multiple open and closed functional spike states of the BA.1 and BA.2 Omicron …


Balancing Functional Tradeoffs Between Protein Stability And Ace2 Binding In The Sars-Cov-2 Omicron Ba.2, Ba.2.75 And Xbb Lineages: Dynamics-Based Network Models Reveal Epistatic Effects Modulating Compensatory Dynamic And Energetic Changes, Gennady M. Verkhivker, Mohammed Alshahrani, Grace Gupta May 2023

Balancing Functional Tradeoffs Between Protein Stability And Ace2 Binding In The Sars-Cov-2 Omicron Ba.2, Ba.2.75 And Xbb Lineages: Dynamics-Based Network Models Reveal Epistatic Effects Modulating Compensatory Dynamic And Energetic Changes, Gennady M. Verkhivker, Mohammed Alshahrani, Grace Gupta

Mathematics, Physics, and Computer Science Faculty Articles and Research

Evolutionary and functional studies suggested that the emergence of the Omicron variants can be determined by multiple fitness trade-offs including the immune escape, binding affinity for ACE2, conformational plasticity, protein stability and allosteric modulation. In this study, we systematically characterize conformational dynamics, structural stability and binding affinities of the SARS-CoV-2 Spike Omicron complexes with the host receptor ACE2 for BA.2, BA.2.75, XBB.1 and XBB.1.5 variants. We combined multiscale molecular simulations and dynamic analysis of allosteric interactions together with the ensemble-based mutational scanning of the protein residues and network modeling of epistatic interactions. This multifaceted computational study characterized molecular mechanisms and …


From Deep Mutational Mapping Of Allosteric Protein Landscapes To Deep Learning Of Allostery And Hidden Allosteric Sites: Zooming In On “Allosteric Intersection” Of Biochemical And Big Data Approaches, Gennady M. Verkhivker, Mohammed Alshahrani, Grace Gupta, Sian Xiao, Peng Tao Apr 2023

From Deep Mutational Mapping Of Allosteric Protein Landscapes To Deep Learning Of Allostery And Hidden Allosteric Sites: Zooming In On “Allosteric Intersection” Of Biochemical And Big Data Approaches, Gennady M. Verkhivker, Mohammed Alshahrani, Grace Gupta, Sian Xiao, Peng Tao

Mathematics, Physics, and Computer Science Faculty Articles and Research

The recent advances in artificial intelligence (AI) and machine learning have driven the design of new expert systems and automated workflows that are able to model complex chemical and biological phenomena. In recent years, machine learning approaches have been developed and actively deployed to facilitate computational and experimental studies of protein dynamics and allosteric mechanisms. In this review, we discuss in detail new developments along two major directions of allosteric research through the lens of data-intensive biochemical approaches and AI-based computational methods. Despite considerable progress in applications of AI methods for protein structure and dynamics studies, the intersection between allosteric …


Coarse-Grained Molecular Simulations And Ensemble-Based Mutational Profiling Of Protein Stability In The Different Functional Forms Of The Sars-Cov-2 Spike Trimers: Balancing Stability And Adaptability In Ba.1, Ba.2 And Ba.2.75 Variants, Gennady M. Verkhivker, Mohammed Alshahrani, Grace Gupta Apr 2023

Coarse-Grained Molecular Simulations And Ensemble-Based Mutational Profiling Of Protein Stability In The Different Functional Forms Of The Sars-Cov-2 Spike Trimers: Balancing Stability And Adaptability In Ba.1, Ba.2 And Ba.2.75 Variants, Gennady M. Verkhivker, Mohammed Alshahrani, Grace Gupta

Mathematics, Physics, and Computer Science Faculty Articles and Research

Evolutionary and functional studies have suggested that the emergence of Omicron variants can be determined by multiple fitness tradeoffs including immune escape, binding affinity, conformational plasticity, protein stability, and allosteric modulation. In this study, we embarked on a systematic comparative analysis of the conformational dynamics, electrostatics, protein stability, and allostery in the different functional states of spike trimers for BA.1, BA.2, and BA.2.75 variants. Using efficient and accurate coarse-grained simulations and atomistic reconstruction of the ensembles, we examined the conformational dynamics of the spike trimers that agree with the recent functional studies, suggesting that BA.2.75 trimers are the most stable …


Identification Of Proteins Involved In Cell Membrane Permeabilization By Nanosecond Electric Pulses (Nsep), Giedre Silkuniene, Uma Mangalanathan, Alessandra Rossi, Peter A. Mollica, Andrei G. Pakhomov, Olga N. Pakhomova Jan 2023

Identification Of Proteins Involved In Cell Membrane Permeabilization By Nanosecond Electric Pulses (Nsep), Giedre Silkuniene, Uma Mangalanathan, Alessandra Rossi, Peter A. Mollica, Andrei G. Pakhomov, Olga N. Pakhomova

Bioelectrics Publications

The study was aimed at identifying endogenous proteins which assist or impede the permeabilized state in the cell membrane disrupted by nsEP (20 or 40 pulses, 300 ns width, 7 kV/cm). We employed a LentiArray CRISPR library to generate knockouts (KOs) of 316 genes encoding for membrane proteins in U937 human monocytes stably expressing Cas9 nuclease. The extent of membrane permeabilization by nsEP was measured by the uptake of Yo-Pro-1 (YP) dye and compared to sham-exposed KOs and control cells transduced with a non-targeting (scrambled) gRNA. Only two KOs, for SCNN1A and CLCA1 genes, showed a statistically significant reduction in …


Phytochemical Investigation Of Egyptian Spinach Leaves, A Potential Source For Antileukemic Metabolites: In Vitro And In Silico Study, Shimaa M. Abdelgawad, Mona H. Hetta, Mohamed A. Ibrahim, Premalatha Balachandran Oct 2022

Phytochemical Investigation Of Egyptian Spinach Leaves, A Potential Source For Antileukemic Metabolites: In Vitro And In Silico Study, Shimaa M. Abdelgawad, Mona H. Hetta, Mohamed A. Ibrahim, Premalatha Balachandran

Faculty and Student Publications

Spinacia oleracea L., Amaranthaceae, leaves cultivated in Egypt demonstrated a potential antileukemic activity against the chronic myeloid leukemia, K562 cell line. Thus, the aim of this study is to carry out a phytochemical investigation of S. oleracea leaves as well as the isolation of its antileukemic phytoconstituents. Phytochemical investigation of S. oleracea leaves resulted in the isolation of seventeen known compounds. The biological study revealed that compounds hexaprenol, phytol, and 18-[(1-oxohexadecyl) oxy]-9-octadecenoic acid exhibited a remarkable antiproliferative activity against K562 cells in vitro. A mechanistic in silico study showed that hexaprenol, phytol, and 18-[(1-oxohexadecyl) oxy]-9-octadecenoic acid exhibited a strong binding …


Probing Mechanisms Of Binding And Allostery In The Sars-Cov-2 Spike Omicron Variant Complexes With The Host Receptor: Revealing Functional Roles Of The Binding Hotspots In Mediating Epistatic Effects And Communication With Allosteric Pockets, Gennady M. Verkhivker, Steve Agajanian, Ryan Kassab, Keerthi Krishnan Sep 2022

Probing Mechanisms Of Binding And Allostery In The Sars-Cov-2 Spike Omicron Variant Complexes With The Host Receptor: Revealing Functional Roles Of The Binding Hotspots In Mediating Epistatic Effects And Communication With Allosteric Pockets, Gennady M. Verkhivker, Steve Agajanian, Ryan Kassab, Keerthi Krishnan

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this study, we performed all-atom MD simulations of RBD–ACE2 complexes for BA.1, BA.1.1, BA.2, and BA.3 Omicron subvariants, conducted a systematic mutational scanning of the RBD–ACE2 binding interfaces and analysis of electrostatic effects. The binding free energy computations of the Omicron RBD–ACE2 complexes and comprehensive examination of the electrostatic interactions quantify the driving forces of binding and provide new insights into energetic mechanisms underlying evolutionary differences between Omicron variants. A systematic mutational scanning of the RBD residues determines the protein stability centers and binding energy hotpots in the Omicron RBD–ACE2 complexes. By employing the ensemble-based global network analysis, we …


Computer Simulations And Network-Based Profiling Of Binding And Allosteric Interactions Of Sars-Cov-2 Spike Variant Complexes And The Host Receptor: Dissecting The Mechanistic Effects Of The Delta And Omicron Mutations, Gennady M. Verkhivker, Steve Agajanian, Ryan Kassab, Keerthi Krishnan Apr 2022

Computer Simulations And Network-Based Profiling Of Binding And Allosteric Interactions Of Sars-Cov-2 Spike Variant Complexes And The Host Receptor: Dissecting The Mechanistic Effects Of The Delta And Omicron Mutations, Gennady M. Verkhivker, Steve Agajanian, Ryan Kassab, Keerthi Krishnan

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this study, we combine all-atom MD simulations and comprehensive mutational scanning of S-RBD complexes with the angiotensin-converting enzyme 2 (ACE2) host receptor in the native form as well as the S-RBD Delta and Omicron variants to (a) examine the differences in the dynamic signatures of the S-RBD complexes and (b) identify the critical binding hotspots and sensitivity of the mutational positions. We also examined the differences in allosteric interactions and communications in the S-RBD complexes for the Delta and Omicron variants. Through the perturbation-based scanning of the allosteric propensities of the SARS-CoV-2 S-RBD residues and dynamics-based network centrality and …


Structural And Computational Studies Of The Sars-Cov-2 Spike Protein Binding Mechanisms With Nanobodies: From Structure And Dynamics To Avidity-Driven Nanobody Engineering, Gennady M. Verkhivker Mar 2022

Structural And Computational Studies Of The Sars-Cov-2 Spike Protein Binding Mechanisms With Nanobodies: From Structure And Dynamics To Avidity-Driven Nanobody Engineering, Gennady M. Verkhivker

Mathematics, Physics, and Computer Science Faculty Articles and Research

Nanobodies provide important advantages over traditional antibodies, including their smaller size and robust biochemical properties such as high thermal stability, high solubility, and the ability to be bioengineered into novel multivalent, multi-specific, and high-affinity molecules, making them a class of emerging powerful therapies against SARS-CoV-2. Recent research efforts on the design, protein engineering, and structure-functional characterization of nanobodies and their binding with SARS-CoV-2 S proteins reflected a growing realization that nanobody combinations can exploit distinct binding epitopes and leverage the intrinsic plasticity of the conformational landscape for the SARS-CoV-2 S protein to produce efficient neutralizing and mutation resistant characteristics. Structural …


Allosteric Determinants Of The Sars-Cov-2 Spike Protein Binding With Nanobodies: Examining Mechanisms Of Mutational Escape And Sensitivity Of The Omicron Variant, Gennady M. Verkhivker Feb 2022

Allosteric Determinants Of The Sars-Cov-2 Spike Protein Binding With Nanobodies: Examining Mechanisms Of Mutational Escape And Sensitivity Of The Omicron Variant, Gennady M. Verkhivker

Mathematics, Physics, and Computer Science Faculty Articles and Research

Structural and biochemical studies have recently revealed a range of rationally engineered nanobodies with efficient neutralizing capacity against the SARS-CoV-2 virus and resilience against mutational escape. In this study, we performed a comprehensive computational analysis of the SARS-CoV-2 spike trimer complexes with single nanobodies Nb6, VHH E, and complex with VHH E/VHH V nanobody combination. We combined coarse-grained and all-atom molecular simulations and collective dynamics analysis with binding free energy scanning, perturbation-response scanning, and network centrality analysis to examine mechanisms of nanobody-induced allosteric modulation and cooperativity in the SARS-CoV-2 spike trimer complexes with these nanobodies. By quantifying energetic and allosteric …


Free Cholesterol Accelerates Aβ Self-Assembly On Membranes At Physiological Concentration, Mohtadin Hashemi, Siddhartha Banerjee, Yuri L. Lyubchenko Jan 2022

Free Cholesterol Accelerates Aβ Self-Assembly On Membranes At Physiological Concentration, Mohtadin Hashemi, Siddhartha Banerjee, Yuri L. Lyubchenko

Journal Articles: Pharmaceutical Sciences

The effects of membranes on the early-stage aggregation of amyloid β (Aβ) have come to light as potential mechanisms by which neurotoxic species are formed in Alzheimer's disease. We have shown that direct Aβ-membrane interactions dramatically enhance the Aβ aggregation, allowing for oligomer assembly at physiologically low concentrations of the monomer. Membrane composition is also a crucial factor in this process. Our results showed that apart from phospholipids composition, cholesterol in membranes significantly enhances the aggregation kinetics. It has been reported that free cholesterol is present in plaques. Here we report that free cholesterol, along with its presence inside the …


Sequentialdynamics Of Stearoyl-Coa Desaturase-1(Scd1)/Ligand Binding And Unbinding Mechanism: A Computational Study, Anna B. Petroff, Rebecca L. Weir, Charles R. Yates, Joseph D. Ng Oct 2021

Sequentialdynamics Of Stearoyl-Coa Desaturase-1(Scd1)/Ligand Binding And Unbinding Mechanism: A Computational Study, Anna B. Petroff, Rebecca L. Weir, Charles R. Yates, Joseph D. Ng

Faculty and Student Publications

Stearoyl-CoA desaturase-1 (SCD1 or delta-9 desaturase, D9D) is a key metabolic protein that modulates cellular inflammation and stress, but overactivity of SCD1 is associated with diseases, including cancer and metabolic syndrome. This transmembrane endoplasmic reticulum protein converts saturated fatty acids into monounsaturated fatty acids, primarily stearoyl-CoA into oleoyl- CoA, which are critical products for energy metabolism and membrane composition. The present computational molecular dynamics study characterizes the molecular dynamics of SCD1 with substrate, product, and as an apoprotein. The modeling of SCD1:fatty acid interactions suggests that: (1) SCD1:CoA moiety interactions open the substrate-binding tunnel, (2) SCD1 stabilizes a substrate conformation …


Molecular-Level Understanding Of The Influence Of Ions And Water On Hmgb1 Adsorption Induced By Surface Hydroxylation Of Titanium Implants, Dineli T. S. Ranathunga, Alexandra Arteaga, Cláudia Cristina Biguetti, Danieli C. Rodrigues, Steven O. Nielsen Aug 2021

Molecular-Level Understanding Of The Influence Of Ions And Water On Hmgb1 Adsorption Induced By Surface Hydroxylation Of Titanium Implants, Dineli T. S. Ranathunga, Alexandra Arteaga, Cláudia Cristina Biguetti, Danieli C. Rodrigues, Steven O. Nielsen

School of Podiatric Medicine Publications and Presentations

Due to its excellent chemical and mechanical properties, titanium has become the material of choice for orthopedic and dental implants to promote rehabilitation via bone anchorage and osseointegration. Titanium osseointegration is partially related to its capability to form a TiO2 surface layer and its ability to interact with key endogenous proteins immediately upon implantation, establishing the first bone–biomaterial interface. Surgical trauma caused by implantation results in the release of high-mobility group box 1 (HMGB1) protein, which is a prototypic DAMP (damage-associated molecular pattern) with multiple roles in inflammation and tissue healing. To develop different surface strategies that improve the clinical …


Conserved Non-Pocket Interactions Drive The Diversity Of Peptide Presentation By Mhc Class I Molecules, Kyle Jackson Aug 2021

Conserved Non-Pocket Interactions Drive The Diversity Of Peptide Presentation By Mhc Class I Molecules, Kyle Jackson

Dissertations & Theses (Open Access)

Cytotoxic T-lymphocytes (CTL) can lyse infected or transformed cells through recognition of peptides presented on human leukocyte antigen (HLA) molecules. A thorough understanding of peptide-HLA interactions is needed for improvement of CTL-based immunotherapies. We observed that aspartic acid (D) and glutamic acid (E) at peptide position 4 are highly prevalent in HLA-I peptide ligands, and discovered that they interact with arginine (R) in position 65 and lysine (L) in position 66 of the α1 helix of the binding groove in HLA-A*0201 and HLA-A*2402. Since this interaction differed from well-characterized peptide-HLA anchor interactions mediated by peptide position 2 and the C-terminus, …


Blue Biotechnology: Computational Screening Of Sarcophyton Cembranoid Diterpenes For Sars-Cov-2 Main Protease Inhibition, Mahmoud A A. Ibrahim, Alaa H M. Abdelrahman, Mohamed A M. Atia, Tarik A. Mohamed, Mahmoud F. Moustafa, Abdulrahim R. Hakami, Shaden A M. Khalifa, Fahad A. Alhumaydhi, Faris Alrumaihi, Syed Hani Abidi Jul 2021

Blue Biotechnology: Computational Screening Of Sarcophyton Cembranoid Diterpenes For Sars-Cov-2 Main Protease Inhibition, Mahmoud A A. Ibrahim, Alaa H M. Abdelrahman, Mohamed A M. Atia, Tarik A. Mohamed, Mahmoud F. Moustafa, Abdulrahim R. Hakami, Shaden A M. Khalifa, Fahad A. Alhumaydhi, Faris Alrumaihi, Syed Hani Abidi

Department of Biological & Biomedical Sciences

The coronavirus pandemic has affected more than 150 million people, while over 3.25 million people have died from the coronavirus disease 2019 (COVID-19). As there are no established therapies for COVID-19 treatment, drugs that inhibit viral replication are a promising target; specifically, the main protease (Mpro) that process CoV-encoded polyproteins serves as an Achilles heel for assembly of replication-transcription machinery as well as down-stream viral replication. In the search for potential antiviral drugs that target Mpro, a series of cembranoid diterpenes from the biologically active soft-coral genus Sarcophyton have been examined as SARS-CoV-2 Mpro inhibitors. Over 360 metabolites from the …


Toward Improving Understanding Of The Structure And Biophysics Of Glycosaminoglycans, Elizabeth K. Whitmore Apr 2021

Toward Improving Understanding Of The Structure And Biophysics Of Glycosaminoglycans, Elizabeth K. Whitmore

Electronic Theses and Dissertations

Glycosaminoglycans (GAGs) are the linear carbohydrate components of proteoglycans (PGs) that mediate PG bioactivities, including signal transduction, tissue morphogenesis, and matrix assembly. To understand GAG function, it is important to understand GAG structure and biophysics at atomic resolution. This is a challenge for existing experimental and computational methods because GAGs are heterogeneous, conformationally complex, and polydisperse, containing up to 200 monosaccharides. Molecular dynamics (MD) simulations come close to overcoming this challenge but are only feasible for short GAG polymers. To address this problem, we developed an algorithm that applies conformations from unbiased all-atom explicit-solvent MD simulations of short GAG polymers …


Graphite/Gold Nanoparticles Electrode For Direct Protein Attachment: Characterization And Gas Sensing Application, Javad Shabani Shayeh, Yahya Sefidbakht, Meisam Omidi, Fatemeh Yazdian, Lobat Tayebi Dec 2020

Graphite/Gold Nanoparticles Electrode For Direct Protein Attachment: Characterization And Gas Sensing Application, Javad Shabani Shayeh, Yahya Sefidbakht, Meisam Omidi, Fatemeh Yazdian, Lobat Tayebi

School of Dentistry Faculty Research and Publications

In this work, graphite/gold nanoparticles (G/AuNPs) were synthesized through a facile chemical method, and its potential application for direct protein attachment for electrochemical detection of carbon monoxide (CO) was investigated. The preparation of G/AuNPs electrodes was optimized by synthesizing the nanoparticles in different concentration of HAuCl4.3H2O at various temperatures. The G/AuNPs electrode was subsequently modified by four types of mercaptopropionic acid, including 1-mercaptopropionic, 3-mercaptopropionic, 6-mercaptopropionic, and 11-mercaptopropionic acid, to achieve the best structure for protein attachment. Visible absorption and electrochemical studies showed that 3-mercaptopropionic acid possesses the best performance regarding the electrical conductivity between electrode and …


Coevolution, Dynamics And Allostery Conspire In Shaping Cooperative Binding And Signal Transmission Of The Sars-Cov-2 Spike Protein With Human Angiotensin-Converting Enzyme 2, Gennady M. Verkhivker Nov 2020

Coevolution, Dynamics And Allostery Conspire In Shaping Cooperative Binding And Signal Transmission Of The Sars-Cov-2 Spike Protein With Human Angiotensin-Converting Enzyme 2, Gennady M. Verkhivker

Mathematics, Physics, and Computer Science Faculty Articles and Research

Binding to the host receptor is a critical initial step for the coronavirus SARS-CoV-2 spike protein to enter into target cells and trigger virus transmission. A detailed dynamic and energetic view of the binding mechanisms underlying virus entry is not fully understood and the consensus around the molecular origins behind binding preferences of SARS-CoV-2 for binding with the angiotensin-converting enzyme 2 (ACE2) host receptor is yet to be established. In this work, we performed a comprehensive computational investigation in which sequence analysis and modeling of coevolutionary networks are combined with atomistic molecular simulations and comparative binding free energy analysis of …


Ionophoric Polyphenols Are Permeable To The Blood Brain Barrier, Interact With Human Serum Albumin And Calf Thymus Dna, And Inhibit Ache Enzymatic Activity, Alberto Martinez, Mai Zahran, Miguel Gomez, Johnny Guevara, Rosemary Pichardo-Bueno, Junaid Asim, Gabriel Ortiz, Yaa Andoh, Sinji Shibutani, Baljit Kaur Aug 2020

Ionophoric Polyphenols Are Permeable To The Blood Brain Barrier, Interact With Human Serum Albumin And Calf Thymus Dna, And Inhibit Ache Enzymatic Activity, Alberto Martinez, Mai Zahran, Miguel Gomez, Johnny Guevara, Rosemary Pichardo-Bueno, Junaid Asim, Gabriel Ortiz, Yaa Andoh, Sinji Shibutani, Baljit Kaur

Publications and Research

Alzheimer’s disease (AD) is the most common form of dementia that affects more than 40 million people around the world. The incidence is expected to rapidly increase due to the lack of any effective treatment. In previous work we synthesized a family of five ionophoric polyphenols (compounds 15) that targeted important aspects related to AD, such as the toxic aggregation of amyloid-β peptides, the production of reactive oxygen species, or the excessive presence of Cu2+ ions. Here, in order to gain insights into their potential therapeutic value, we have tested the ability of compounds 1– …


Network Approaches To Elucidate The Determinants Of Protein Topology And Stability, Zeinab Haratipour Apr 2020

Network Approaches To Elucidate The Determinants Of Protein Topology And Stability, Zeinab Haratipour

Chemistry & Biochemistry Theses & Dissertations

Predicting three-dimensional structures of proteins from sequence information alone, remains one of the most profoundly challenging and intensely studied problems in basic science. It has uniquely garnered the interdisciplinary efforts of biologists, biochemists, computer scientists, mathematicians and physicists. The advancement of computational methods to study fundamental features of proteins also enables insights that are either difficult to explore experimentally or complimentary to further interpret experimental data. In the present research and through the combined development and application of molecular dynamics and network science approaches we aimed to elucidate the role of geographically important amino acids and evolutionarily conserved long-range interactions …


Stimulation Of Heat Shock Protein 90 Chaperone Function Through Binding Of A Novobiocin Analog Ku-32, Bhaskar K. Chatterjee, Abhilash Jayaraj, Vinay Kumar, Brian Blagg, Rachel E. Davis, B Jayaram, Shashank Deep, Tapan K. Chaudhuri Apr 2019

Stimulation Of Heat Shock Protein 90 Chaperone Function Through Binding Of A Novobiocin Analog Ku-32, Bhaskar K. Chatterjee, Abhilash Jayaraj, Vinay Kumar, Brian Blagg, Rachel E. Davis, B Jayaram, Shashank Deep, Tapan K. Chaudhuri

Faculty Publications

Heat shock protein 90 (Hsp90) is a eukaryotic chaperone responsible for the folding and functional activation of numerous client proteins, many of which are oncoproteins. Thus, Hsp90 inhibition has been intensely pursued, resulting in the development of many potential Hsp90 inhibitors, not all of which are well-characterized. Hsp90 inhibitors not only abrogate its chaperone functions, but also could help us gain insight into the structure-function relationship of this chaperone. Here, using biochemical and cell-based assays along with isothermal titration calorimetry, we investigate KU-32, a derivative of the Hsp90 inhibitor novobiocin (NB), for its ability to modulate Hsp90 chaperone function. Although …


Schinus Molle: Anatomy Of Leaves And Stems, Chemical Composition And Insecticidal Activities Of Volatile Oil Against Bed Bug (Cimex Lectularius), Camila D. Machado, Vijayasankar Raman, Junaid U. Rehman, Beatriz H.L.N.S. Maia, Emanuelle K. Meneghetti, Valter P. Almeida, Rosi Z. Silva, Paulo V. Farago, Ikhlas A. Khan, Jane M. Budel Jan 2019

Schinus Molle: Anatomy Of Leaves And Stems, Chemical Composition And Insecticidal Activities Of Volatile Oil Against Bed Bug (Cimex Lectularius), Camila D. Machado, Vijayasankar Raman, Junaid U. Rehman, Beatriz H.L.N.S. Maia, Emanuelle K. Meneghetti, Valter P. Almeida, Rosi Z. Silva, Paulo V. Farago, Ikhlas A. Khan, Jane M. Budel

Faculty and Student Publications

© 2019 by the authors The investigation of the constituents that were isolated from Turnera diffusa (damiana) for their inhibitory activities against recombinant human monoamine oxidases (MAO-A and MAO-B) in vitro identified acacetin 7-methyl ether as a potent selective inhibitor of MAO-B (IC50 = 198 nM). Acacetin 7-methyl ether (also known as 5-hydroxy-40, 7-dimethoxyflavone) is a naturally occurring flavone that is present in many plants and vegetables. Acacetin 7-methyl ether was four-fold less potent as an inhibitor of MAO-B when compared to acacetin (IC50 = 50 nM). However, acacetin 7-methyl ether was >500-fold selective against MAO-B over MAO-A as compared …


Domain Rearrangement And Denaturation In Ebola Virus Protein Vp40, Rudramani Pokhrel, Pornthep Sompornpisut, Prem Chapagain, Brian Olson, Bernard Gertsman, Ras B. Pandey Dec 2018

Domain Rearrangement And Denaturation In Ebola Virus Protein Vp40, Rudramani Pokhrel, Pornthep Sompornpisut, Prem Chapagain, Brian Olson, Bernard Gertsman, Ras B. Pandey

Faculty Publications

The VP40 protein plays a critical role in coordinating the virion assembly, budding, and replication of the Ebola virus. Efforts have been made in recent years to understand various aspects of VP40 structure, dynamics, and function such as assembly of the protein and its roles in virus replication and penetration of the protein into the plasma membrane. A major conformational transformation is necessary for VP40 to form some of its oligomeric structures and to perform various functions. This conformational change from a compact structure with the N-terminal domain (NTD) and C-terminal domain (CTD) closely associated involves a dissociation or springing-out …


Structure Based Drug Design Of High Affinity Kras Inhibitors, Michael Mccarthy May 2018

Structure Based Drug Design Of High Affinity Kras Inhibitors, Michael Mccarthy

Dissertations & Theses (Open Access)

RAS, one of the most well characterized membrane-associated small GTPases, is a notorious oncogene with >15% of all tumors harboring RAS mutations. When RAS is mutated it becomes constitutively active sending cell growth, survival and proliferation into overdrive, which subsequently leads to cancer. Although, RAS has been aggressively targeted with drug design efforts for more than 30 years an FDA approved direct inhibitor has not yet been developed. There are three isoforms of RAS in cells; HRAS, NRAS and KRAS. We focused on KRAS since it is the most frequently mutated isoform in cancer. To identify novel non-covalent small molecules …


Anti-Correlation Between The Dynamics Of The Active Site Loop And C-Terminal Tail In Relation To The Homodimer Asymmetry Of The Mouse Erythroid 5-Aminolevulinate Synthase, Insung Na, Dominique Catena, Min J. Kong, Gloria C. Ferreira, Vladimir N. Uversky Jan 2018

Anti-Correlation Between The Dynamics Of The Active Site Loop And C-Terminal Tail In Relation To The Homodimer Asymmetry Of The Mouse Erythroid 5-Aminolevulinate Synthase, Insung Na, Dominique Catena, Min J. Kong, Gloria C. Ferreira, Vladimir N. Uversky

Molecular Medicine Faculty Publications

Biosynthesis of heme represents a complex process that involves multiple stages controlled by different enzymes. The first of these proteins is a pyridoxal 5′-phosphate (PLP)-dependent homodimeric enzyme, 5-aminolevulinate synthase (ALAS), that catalyzes the rate-limiting step in heme biosynthesis, the condensation of glycine with succinyl-CoA. Genetic mutations in human erythroid-specific ALAS (ALAS2) are associated with two inherited blood disorders, X-linked sideroblastic anemia (XLSA) and X-linked protoporphyria (XLPP). XLSA is caused by diminished ALAS2 activity leading to decreased ALA and heme syntheses and ultimately ineffective erythropoiesis, whereas XLPP results from “gain-of-function” ALAS2 mutations and consequent overproduction of protoporphyrin IX and increase in …


Improving The Thermal Stability Of Cellobiohydrolase Cel7a From Hypocrea Jecorina By Directed Evolution, Frits Goedegebuur, Lydia Dankmeyer, Peter Gualfetti, Saeid Karkehabadi, Henrik Hansson, Suvamay Jana, Vicky Huynh, Bradley R. Kelemen, Paulien Kruithof, Edmund A. Larenas, Pauline J. M. Teunissen, Jerry Ståhlberg, Christina M. Payne, Colin Mitchinson, Mats Sandgren Aug 2017

Improving The Thermal Stability Of Cellobiohydrolase Cel7a From Hypocrea Jecorina By Directed Evolution, Frits Goedegebuur, Lydia Dankmeyer, Peter Gualfetti, Saeid Karkehabadi, Henrik Hansson, Suvamay Jana, Vicky Huynh, Bradley R. Kelemen, Paulien Kruithof, Edmund A. Larenas, Pauline J. M. Teunissen, Jerry Ståhlberg, Christina M. Payne, Colin Mitchinson, Mats Sandgren

Chemical and Materials Engineering Faculty Publications

Secreted mixtures of Hypocrea jecorina cellulases are able to efficiently degrade cellulosic biomass to fermentable sugars at large, commercially relevant scales. H. jecorina Cel7A, cellobiohydrolase I, from glycoside hydrolase family 7, is the workhorse enzyme of the process. However, the thermal stability of Cel7A limits its use to processes where temperatures are no higher than 50 °C. Enhanced thermal stability is desirable to enable the use of higher processing temperatures and to improve the economic feasibility of industrial biomass conversion. Here, we enhanced the thermal stability of Cel7A through directed evolution. Sites with increased thermal stability properties were combined, and …


Structural And Functional Analysis Of A Β2-Adrenergic Receptor Complex With Grk5., Konstantin E. Komolov, Yang Du, Nguyen Minh Duc, Robin M. Betz, João P.G.L.M. Rodrigues, Ryan D. Leib, Dhabaleswar Patra, Georgios Skiniotis, Christopher M. Adams, Ron O. Dror, Ka Young Chung, Brian K. Kobilka, Jeffrey L. Benovic Apr 2017

Structural And Functional Analysis Of A Β2-Adrenergic Receptor Complex With Grk5., Konstantin E. Komolov, Yang Du, Nguyen Minh Duc, Robin M. Betz, João P.G.L.M. Rodrigues, Ryan D. Leib, Dhabaleswar Patra, Georgios Skiniotis, Christopher M. Adams, Ron O. Dror, Ka Young Chung, Brian K. Kobilka, Jeffrey L. Benovic

Department of Biochemistry and Molecular Biology Faculty Papers

The phosphorylation of agonist-occupied G-protein-coupled receptors (GPCRs) by GPCR kinases (GRKs) functions to turn off G-protein signaling and turn on arrestin-mediated signaling. While a structural understanding of GPCR/G-protein and GPCR/arrestin complexes has emerged in recent years, the molecular architecture of a GPCR/GRK complex remains poorly defined. We used a comprehensive integrated approach of cross-linking, hydrogen-deuterium exchange mass spectrometry (MS), electron microscopy, mutagenesis, molecular dynamics simulations, and computational docking to analyze GRK5 interaction with the β2-adrenergic receptor (β2AR). These studies revealed a dynamic mechanism of complex formation that involves large conformational changes in the GRK5 RH/catalytic domain interface upon receptor binding. …