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Articles 31 - 60 of 288

Full-Text Articles in Chemistry

Carbohydrate Metabolism In Bacteria: Alternative Specificities In Adp-Glucose Pyrophosphorylases Open Novel Metabolic Scenarios And Biotechnological Tools, Jaina A. Bhayani, Maria Josefina Iglesias, Romina I. Minen, Antonela E. Cereijo, Miguel Ballicora, Alberto A. Iglesias, Matias D. Asencion Diez Apr 2022

Carbohydrate Metabolism In Bacteria: Alternative Specificities In Adp-Glucose Pyrophosphorylases Open Novel Metabolic Scenarios And Biotechnological Tools, Jaina A. Bhayani, Maria Josefina Iglesias, Romina I. Minen, Antonela E. Cereijo, Miguel Ballicora, Alberto A. Iglesias, Matias D. Asencion Diez

Chemistry: Faculty Publications and Other Works

We explored the ability of ADP-glucose pyrophosphorylase (ADP-Glc PPase) from different bacteria to use glucosamine (GlcN) metabolites as a substrate or allosteric effectors. The enzyme from the actinobacteria Kocuria rhizophila exhibited marked and distinctive sensitivity to allosteric activation by GlcN-6P when producing ADP-Glc from glucose-1-phosphate (Glc-1P) and ATP. This behavior is also seen in the enzyme from Rhodococcus spp., the only one known so far to portray this activation. GlcN-6P had a more modest effect on the enzyme from other Actinobacteria (Streptomyces coelicolor), Firmicutes (Ruminococcus albus), and Proteobacteria (Agrobacterium tumefaciens) groups. In addition, we …


Repurposing Lansoprazole And Posaconazole To Treat Leishmaniasis: Integration Of In Vitro Testing, Pharmacological Corroboration, And Mechanisms Of Action, Yash Gupta, Steven Goicoechea, Jesus G. Romero, Raman Mathur, Thomas R. Caulfield, Daniel P. Becker, Ravi Durvasula, Prakasha Kempaiah Mar 2022

Repurposing Lansoprazole And Posaconazole To Treat Leishmaniasis: Integration Of In Vitro Testing, Pharmacological Corroboration, And Mechanisms Of Action, Yash Gupta, Steven Goicoechea, Jesus G. Romero, Raman Mathur, Thomas R. Caulfield, Daniel P. Becker, Ravi Durvasula, Prakasha Kempaiah

Chemistry: Faculty Publications and Other Works

Leishmaniasis remains a serious public health problem in many tropical regions of the world. Among neglected tropical diseases, the mortality rate of leishmaniasis is second only to malaria. All currently approved therapeutics have toxic side effects and face rapidly increasing resistance. To identify existing drugs with antileishmanial activity and predict the mechanism of action, we designed a drug-discovery pipeline utilizing both in-silico and in-vitro methods. First, we screened compounds from the Selleckchem Bio-Active Compound Library containing ~1622 FDA-approved drugs and narrowed these down to 96 candidates based on data mining for possible anti-parasitic properties. Next, we completed preliminary in-vitro testing …


Determination Of Dissociation Constants Of Protein Ligands By Thermal Shift Assay, Jaina A. Bhayani, Miguel Ballicora Jan 2022

Determination Of Dissociation Constants Of Protein Ligands By Thermal Shift Assay, Jaina A. Bhayani, Miguel Ballicora

Chemistry: Faculty Publications and Other Works

The thermal shift assay (TSA) is a powerful tool used to detect molecular interactions between proteins and ligands. Using temperature as a physical denaturant and an extrinsic fluorescent dye, the TSA tracks protein unfolding. This method precisely determines the midpoint of the unfolding transition (Tm" role="presentation">), which can shift upon the addition of a ligand. Though experimental protocols have been well developed, the thermal shift assay data traditionally yielded qualitative results. Quantitative methods for Kd" role="presentation"> determination relied either on empirical and inaccurate usage of Tm" role="presentation"> or on isothermal approaches, which do not take full advantage of the …


Iron Dysregulation In Covid-19 And Reciprocal Evolution Of Sars-Cov-2: Natura Nihil Frustra Facit, Yash Gupta, Dawid Maciorowski, Brian Medernach, Daniel P. Becker Ph.D., Ravi Durvasula, Claudia R. Libertin, Prakasha Kempaiah Jan 2022

Iron Dysregulation In Covid-19 And Reciprocal Evolution Of Sars-Cov-2: Natura Nihil Frustra Facit, Yash Gupta, Dawid Maciorowski, Brian Medernach, Daniel P. Becker Ph.D., Ravi Durvasula, Claudia R. Libertin, Prakasha Kempaiah

Chemistry: Faculty Publications and Other Works

After more than a year of the COVID-19 pandemic, SARS-CoV-2 infection rates with newer variants continue to devastate much of the world. Global healthcare systems are overwhelmed with high positive patient numbers. Silent hypoxia accompanied by rapid deterioration and some cases with septic shock is responsible for COVID-19 mortality in many hospitalized patients. There is an urgent need to further understand the relationships and interplay with human host components during pathogenesis and immune evasion strategies. Currently, acquired immunity through vaccination or prior infection usually provides sufficient protection against the emerging variants of SARS-CoV-2 except Omicron variant requiring recent booster. New …


Synthesis And Characterization Of Ruthenium Complexes And Their Potential And Photosensitizers For Photodynamic Therapy, Keit Dine Jan 2022

Synthesis And Characterization Of Ruthenium Complexes And Their Potential And Photosensitizers For Photodynamic Therapy, Keit Dine

Master's Theses

Cancer is one of the leading causes of death in the world with over 10 million people dying of the disease every year. Inorganic complexes supported by platinum metal centers are often used in cancer treatment. However, these complexes lack selectivity for tumor cells. As such, other alternatives to platinum have been explored. Ruthenium (Ru) complexes are one of the most promising candidates due to their ability to be used as photosensitizing drugs in photodynamic therapy. Herein, we report the design, synthesis, and characterization of two novel ruthenium-based complexes. One compound is a Ru(II) homoleptic complex, while the other is …


Rhodium-Catalyzed Decarbonylation Of Aroyl Chlorides, Wiktoria M. Koza Jan 2022

Rhodium-Catalyzed Decarbonylation Of Aroyl Chlorides, Wiktoria M. Koza

Dissertations

The development of efficient strategies for the synthesis of aryl–halogen bonds is highly desirable due to the prevalence of these moieties in pharmaceuticals, agrochemicals, and organic synthesis. Although there are numerous applications of aryl chlorides in chemistry, an efficient strategy for the preparation of these molecules is underdeveloped. Transition metal-catalyzed decarbonylation provides an efficient and selective approach for aryl–halogen bond formation. There has been significant progress in the development of new decarbonylation strategies, particularly involving aldehydes for the synthesis of new carbon–hydrogen (C–H) bonds or for cross-coupling reactions. However, transition metal-catalyzed decarbonylation methods for carbon–halogen (C–X) bond formation have been …


Biocatalytic Intramolecular C−H Aminations Via Engineered Heme Proteins: Full Reaction Pathways And Axial Ligand Effects, Yang Wei, Melissa Conklin, Yong Zhang Jan 2022

Biocatalytic Intramolecular C−H Aminations Via Engineered Heme Proteins: Full Reaction Pathways And Axial Ligand Effects, Yang Wei, Melissa Conklin, Yong Zhang

Chemistry: Faculty Publications and Other Works

Engineered heme protein biocatalysts provide an efficient and sustainable approach to develop amine-containing compounds through C−H amination. A quantum chemical study to reveal the complete heme catalyzed intramolecular C−H amination pathway and protein axial ligand effect was reported, using reactions of an experimentally used arylsulfonylazide with hemes containing L=none, SH−, MeO−, and MeOH to simulate no axial ligand, negatively charged Cys and Ser ligands, and a neutral ligand for comparison. Nitrene formation was found as the overall rate-determining step (RDS) and the catalyst with Ser ligand has the best reactivity, consistent with experimental reports. Both RDS and non-RDS (nitrene transfer) …


Bisindolylmaleimide Ix: A Novel Anti-Sars-Cov2 Agent Targeting Viral Main Protease 3clpro Demonstrated By Virtual Screening Pipeline And In-Vitro Validation Assays, Yash Gupta, Dawid Maciorowski, Samantha E. Zak, Krysten A. Jones, Rahul S. Kathayat, Saara-Anne Azizi, Raman Mathur, Catherine M. Pearce, David J. Ilc, Hamza Husein, Andrew S. Herbert, Ajay Bharti, Brijesh Rathi, Ravi Durvasula, Daniel P. Becker, Bryan C. Dickinson, John M. Dye, Prakasha Kempaiah Nov 2021

Bisindolylmaleimide Ix: A Novel Anti-Sars-Cov2 Agent Targeting Viral Main Protease 3clpro Demonstrated By Virtual Screening Pipeline And In-Vitro Validation Assays, Yash Gupta, Dawid Maciorowski, Samantha E. Zak, Krysten A. Jones, Rahul S. Kathayat, Saara-Anne Azizi, Raman Mathur, Catherine M. Pearce, David J. Ilc, Hamza Husein, Andrew S. Herbert, Ajay Bharti, Brijesh Rathi, Ravi Durvasula, Daniel P. Becker, Bryan C. Dickinson, John M. Dye, Prakasha Kempaiah

Chemistry: Faculty Publications and Other Works

SARS-CoV-2, the virus that causes COVID-19 consists of several enzymes with essential functions within its proteome. Here, we focused on repurposing approved and investigational drugs/compounds. We targeted seven proteins with enzymatic activities known to be essential at different stages of the viral cycle including PLpro, 3CLpro, RdRP, Helicase, ExoN, NendoU, and 2′-O-MT. For virtual screening, energy minimization of a crystal structure of the modeled protein was carried out using the Protein Preparation Wizard (Schrodinger LLC 2020-1). Following active site selection based on data mining and COACH predictions, we performed a high-throughput virtual screen of drugs and investigational molecules (n = …


Oxygen-Induced Surface Reconstructions On Curved Ag(111), Marie Turano, Ludo B. F. Juurlink, Maxwell Z. Gillum, Elizabeth A. Jamka, George Hildebrandt, Faith J. Lewis, Daniel Killelea Oct 2021

Oxygen-Induced Surface Reconstructions On Curved Ag(111), Marie Turano, Ludo B. F. Juurlink, Maxwell Z. Gillum, Elizabeth A. Jamka, George Hildebrandt, Faith J. Lewis, Daniel Killelea

Chemistry: Faculty Publications and Other Works

The adsorption of oxygen and the resultant O-induced surface reconstructions are key components in heterogeneously catalyzed reactions on silver metal surfaces. O uptake and reconstructions on planar Ag(111) are well-characterized, and in this paper, we show that curved Ag(111) features similar O adsorption and reconstructions. Through a systematic scanning tunneling microscope study of a curved Ag(111) single crystal exposed to gas-phase atomic oxygen at a temperature of 525 K, we observed Oad and, upon higher coverages, saw p(4 4) and p(4 5 p3) reconstructions form on both the A-type and B-type steps. Exposures at low temperatures (< 500 K) resulted in the formation of subsurface oxygen and the appearance of a stripe pattern and amorphous phase on the surface. Upon heating, stable surface reconstructions were formed. Although the geometric arrangement of atoms along the steps were different, A-type and B-type steps formed the same reconstructions. In addition, the B-type steps also saw the formation of several different features atop the oxygen reconstructions.


Quantifying Phosphatidylethanol From Blood Samples, James V. Defrancesco, Majid Afshar Aug 2021

Quantifying Phosphatidylethanol From Blood Samples, James V. Defrancesco, Majid Afshar

Chemistry: Faculty Publications and Other Works

Disclosed herein is a method for quantifying phosphatidylethanol (“ PEth ”), direct ethanol biomarker, from a blood sample using gas chromatography mass spectrometry. The method disclosed herein is useful for diagnosing acute and chronic alcohol abuse.


Bridging The 12-6-4 Model And The Fluctuating Charge Model, Pengfei Li Jul 2021

Bridging The 12-6-4 Model And The Fluctuating Charge Model, Pengfei Li

Chemistry: Faculty Publications and Other Works

Metal ions play important roles in various biological systems. Molecular dynamics (MD) using classical force field has become a popular research tool to study biological systems at the atomic level. However, meaningful MD simulations require reliable models and parameters. Previously we showed that the 12-6 Lennard-Jones nonbonded model for ions could not reproduce the experimental hydration free energy (HFE) and ion-oxygen distance (IOD) values simultaneously when ion has a charge of +2 or higher. We discussed that this deficiency arises from the overlook of the ion-induced dipole interaction in the 12-6 model, and this term is proportional to 1/r …


Extraction And Analysis Of Eugenol From Cloves, James V. Defrancesco May 2021

Extraction And Analysis Of Eugenol From Cloves, James V. Defrancesco

Chemistry: Faculty Publications and Other Works

This paper describes a laboratory procedure for the extraction and identification of eugenol from cloves (Syzygium aromaticum L.). The purpose is to instruct students in the isolation and identification of a medicinally relevant compound from a plant via simple solvent extraction. The analytical tools employed to identify eugenol and other naturally occurring chemical components in the cloves extract include color tests, thin layer chromatography (TLC), infrared spectrophotometry (IR), and gas chromatography coupled to mass spectrometry (GC-MS). In addition to eugenol, the cloves extract contains acetyl eugenol which can be distinguished from eugenol by several test methods. Triethylamine is used as …


Cyclobutanone Inhibitor Of Cobalt-Functionalized Metallo-Γ-Lactonase Aiia With Cyclobutanone Ring Opening In The Active Site, Cory T. Reidl, Romila Mascarenhas, Thahani S. Habeeb Mohammad, Marlon R. Lutz Jr, Pei W. Thomas, Walter Fast, Dali Liu, Daniel P. Becker Ph.D. May 2021

Cyclobutanone Inhibitor Of Cobalt-Functionalized Metallo-Γ-Lactonase Aiia With Cyclobutanone Ring Opening In The Active Site, Cory T. Reidl, Romila Mascarenhas, Thahani S. Habeeb Mohammad, Marlon R. Lutz Jr, Pei W. Thomas, Walter Fast, Dali Liu, Daniel P. Becker Ph.D.

Chemistry: Faculty Publications and Other Works

An α-amido cyclobutanone possessing a C10 hydrocarbon tail was designed as a potential transition-state mimetic for the quorum-quenching metallo-γ-lactonase autoinducer inactivator A (AiiA) with the support of in-house modeling techniques and found to be a competitive inhibitor of dicobalt(II) AiiA with an inhibition constant of Ki = 0.007 ± 0.002 mM. The catalytic mechanism of AiiA was further explored using our product-based transition-state modeling (PBTSM) computational approach, providing substrate-intermediate models arising during enzyme turnover and further insight into substrate–enzyme interactions governing native substrate catalysis. These interactions were targeted in the docking of cyclobutanone hydrates into the active site of …


Gcn5-Related N-Acetyltransferases (Gnats) With A Catalytic Serine Residue Can Play Ping-Pong Too, Jackson T. Baumgartner, Thahani S. Habeeb Mohammad, Mateusz P. Czub, Karolina A. Majorek, Xhulio Arolli, Cillian Variot, Madison Anonick, Wladek Minor, Miguel A. Ballicora, Daniel P. Becker Ph.D., Misty L. Kuhn Apr 2021

Gcn5-Related N-Acetyltransferases (Gnats) With A Catalytic Serine Residue Can Play Ping-Pong Too, Jackson T. Baumgartner, Thahani S. Habeeb Mohammad, Mateusz P. Czub, Karolina A. Majorek, Xhulio Arolli, Cillian Variot, Madison Anonick, Wladek Minor, Miguel A. Ballicora, Daniel P. Becker Ph.D., Misty L. Kuhn

Chemistry: Faculty Publications and Other Works

Enzymes in the Gcn5-related N-acetyltransferase (GNAT) superfamily are widespread and critically involved in multiple cellular processes ranging from antibiotic resistance to histone modification. While acetyl transfer is the most widely catalyzed reaction, recent studies have revealed that these enzymes are also capable of performing succinylation, condensation, decarboxylation, and methylcarbamoylation reactions. The canonical chemical mechanism attributed to GNATs is a general acid/base mechanism; however, mounting evidence has cast doubt on the applicability of this mechanism to all GNATs. This study shows that the Pseudomonas aeruginosa PA3944 enzyme uses a nucleophilic serine residue and a hybrid ping-pong mechanism for catalysis instead …


Atomic-Resolution 1.3 Å Crystal Structure, Inhibition By Sulfate, And Molecular Dynamics Of The Bacterial Enzyme Dape, Matthew Kochert, Boguslaw P. Nocek, Thahani S. Habeeb Mohammad, Elliot Gild, Kaitlyn Lovato, Tahirah K. Heath, Richard C. Holz, Kenneth W. Olsen, Daniel P. Becker Ph.D. Mar 2021

Atomic-Resolution 1.3 Å Crystal Structure, Inhibition By Sulfate, And Molecular Dynamics Of The Bacterial Enzyme Dape, Matthew Kochert, Boguslaw P. Nocek, Thahani S. Habeeb Mohammad, Elliot Gild, Kaitlyn Lovato, Tahirah K. Heath, Richard C. Holz, Kenneth W. Olsen, Daniel P. Becker Ph.D.

Chemistry: Faculty Publications and Other Works

We report the atomic-resolution (1.3 Å) X-ray crystal structure of an open conformation of the dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase (DapE, EC 3.5.1.18) from Neisseria meningitidis. This structure [Protein Data Bank (PDB) entry 5UEJ] contains two bound sulfate ions in the active site that mimic the binding of the terminal carboxylates of the N-succinyl-l,l-diaminopimelic acid (l,l-SDAP) substrate. We demonstrated inhibition of DapE by sulfate (IC50 = 13.8 ± 2.8 mM). Comparison with other DapE structures in the PDB demonstrates the flexibility of the interdomain connections of this protein. This high-resolution structure was then utilized as the …


Exposing The Effects Of Reaction Cavity In Solid-Phase Reaction Kinetics, Michael Carr Jan 2021

Exposing The Effects Of Reaction Cavity In Solid-Phase Reaction Kinetics, Michael Carr

Master's Theses

Reactivity of molecular solids is governed by topochemical considerations, where minimizedmolecular movement dictates both product identity and kinetics. This Thesis explores the central role reaction cavity plays in the topochemical principle by using the highly varied cavities formed by the different facets of a tetracene crystal. The relative rates for ten different reaction cavities were measured via energy dispersive X-ray spectroscopy for the reaction of tetracene with vapors of maleic anhydride. Variance in cavities resulted in Diels-Alder reaction rates that differed by as much as a factor of 2.6. Effects were understood via molecular dynamic simulations which modeled the approach …


Identification Of New Pathways For Co Oxidation On Rh(111) & Spatial And Structural Control Of O-Induced Reconstruction Of Ag(111), Marie Turano Jan 2021

Identification Of New Pathways For Co Oxidation On Rh(111) & Spatial And Structural Control Of O-Induced Reconstruction Of Ag(111), Marie Turano

Dissertations

Understanding the fundamentals of oxygen surface structures under a variety of conditions is pivotal to determining reactivity of heterogeneous catalysis. Exposure of catalytically active metal surfaces to high oxygen coverages results in a myriad of surface structures. A further complication is the formation of subsurface oxygen (Osub) or oxygen present in the near subsurface region of the metal. It is known to form in transition metals yet the absorption of oxygen and resultant formation of Osub is not equivalent across all catalytically relevant metals. As a result, it is difficult to predict the stability and efficacy of the formation of …


Development Of Small Molecule Inhibitors Of Therapeutic Target Enzymes: Paths To Discover Novel Antimicrobials, Thahani Shifna Habeeb Mohammad Jan 2021

Development Of Small Molecule Inhibitors Of Therapeutic Target Enzymes: Paths To Discover Novel Antimicrobials, Thahani Shifna Habeeb Mohammad

Dissertations

The rising antimicrobial resistance to antibiotics is a major global problem, which has been exacerbated by the inappropriate use of antibiotics. The effectiveness of frequently prescribed penicillin derivatives and β-lactamase inhibitors are compromised by the evolution of bacterial β-lactamases and antibiotic-resistant bacteria. Consequently, design and synthesis of small-molecule inhibitors of identified novel antibiotic targets is an urgent unmet medical need. We previously demonstrated that N-functionalized α-aminocyclobutanones can act as peptidomimetic enzyme inhibitors, including inhibition of a key esterase in Francisella Tularensis. The carbonyl of a cyclobutanone is electrophilic due to ring strain, therefore cyclobutanone derivatives can serve as transition state …


Synthesis And Characterization Of Redox Non-Innocent Ligand Supported Transition Metal Complexes, Adriana Marie Lugosan Jan 2021

Synthesis And Characterization Of Redox Non-Innocent Ligand Supported Transition Metal Complexes, Adriana Marie Lugosan

Dissertations

Catalysis is an integral part of society, which is often taken for granted. Over the past few years, there has been an increased effort to develop catalysts that are more environmentally friendly, selective, and energy efficient. This work focuses on the development of novel complexes made from a carefully designed non-innocent ligand together with earth-abundant and cost-effective transition metals that can be used to understand fundamental inorganic chemistry principles and serve as model systems. The work reported within validates the utility of this novel class of redox non-innocent ligand to form metal complexes with interesting properties, such as a non-porphyrin …


A Review Of The Preclinical And Clinical Efficacy Of Remdesivir, Hydroxychloroquine, And Lopinavir-Ritonavir Treatments Against Covid-19, Dawid Maciorowski, Samir Z. El Idrissi, Yash Gupta, Brian J. Medernach, Michael B. Burns, Daniel P. Becker Ph.D., Ravi Durvasula, Prakasha Kempaiah Sep 2020

A Review Of The Preclinical And Clinical Efficacy Of Remdesivir, Hydroxychloroquine, And Lopinavir-Ritonavir Treatments Against Covid-19, Dawid Maciorowski, Samir Z. El Idrissi, Yash Gupta, Brian J. Medernach, Michael B. Burns, Daniel P. Becker Ph.D., Ravi Durvasula, Prakasha Kempaiah

Chemistry: Faculty Publications and Other Works

In December of 2019, an outbreak of a novel coronavirus flared in Wuhan, the capital city of the Hubei Province, China. The pathogen has been identified as a novel enveloped RNA beta-coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The virus SARS-CoV-2 is associated with a disease characterized by severe atypical pneumonia known as coronavirus 2019 (COVID-19). Typical symptoms of this disease include cough, fever, malaise, shortness of breath, gastrointestinal symptoms, anosmia, and, in severe cases, pneumonia.1 The high-risk group of COVID-19 patients includes people over the age of 60 years as well as people with existing cardiovascular …


Indoline‐6‐Sulfonamide Inhibitors Of The Bacterial Enzyme Dape, Cory T. Reidl, Tahirah K. Heath, Iman Darwish, Rachel M. Torrez, Maxwell Moore, Elliot Gild, Boguslaw P. Nocek, Anna Starus, Richard C. Holz, Daniel P. Becker Ph.D. Sep 2020

Indoline‐6‐Sulfonamide Inhibitors Of The Bacterial Enzyme Dape, Cory T. Reidl, Tahirah K. Heath, Iman Darwish, Rachel M. Torrez, Maxwell Moore, Elliot Gild, Boguslaw P. Nocek, Anna Starus, Richard C. Holz, Daniel P. Becker Ph.D.

Chemistry: Faculty Publications and Other Works

Inhibitors of the bacterial enzyme dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase (DapE; EC 3.5.1.18) hold promise as antibiotics with a new mechanism of action. Herein we describe the discovery of a new series of indoline sulfonamide DapE inhibitors from a high-throughput screen and the synthesis of a series of analogs. Inhibitory potency was measured by a ninhydrin-based DapE assay recently developed by our group. Molecular docking experiments suggest active site binding with the sulfonamide acting as a zinc-binding group (ZBG).


Indoline-6-Sulfonamide Inhibitors Of The Bacterial Enzyme Dape, Cory T. Reidl, Tahirah K. Heath, Iman Darwish, Rachel M. Torrez, Maxwell Moore, Elliot Gild, Boguslaw P. Nocek, Anna Starus, Richard C. Holz, Daniel P. Becker Ph.D. Sep 2020

Indoline-6-Sulfonamide Inhibitors Of The Bacterial Enzyme Dape, Cory T. Reidl, Tahirah K. Heath, Iman Darwish, Rachel M. Torrez, Maxwell Moore, Elliot Gild, Boguslaw P. Nocek, Anna Starus, Richard C. Holz, Daniel P. Becker Ph.D.

Chemistry: Faculty Publications and Other Works

Inhibitors of the bacterial enzyme dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase (DapE; EC 3.5.1.18) hold promise as antibiotics with a new mechanism of action. Herein we describe the discovery of a new series of indoline sulfonamide DapE inhibitors from a high-throughput screen and the synthesis of a series of analogs. Inhibitory potency was measured by a ninhydrin-based DapE assay recently developed by our group. Molecular docking experiments suggest active site binding with the sulfonamide acting as a zinc-binding group (ZBG).


Carborane‐Containing Matrix Metalloprotease (Mmp) Ligands As Candidates For Boron Neutron‐Capture Therapy (Bnct), Marlon R. Lutz Jr, Sebastian Flieger, Andre Colorina, John Wozny, Narayan S. Hosmane, Daniel P. Becker Ph.D. Jul 2020

Carborane‐Containing Matrix Metalloprotease (Mmp) Ligands As Candidates For Boron Neutron‐Capture Therapy (Bnct), Marlon R. Lutz Jr, Sebastian Flieger, Andre Colorina, John Wozny, Narayan S. Hosmane, Daniel P. Becker Ph.D.

Chemistry: Faculty Publications and Other Works

Based on the previously reported potent and selective sulfone hydroxamate inhibitors SC‐76276, SC‐78080 (SD‐2590), and SC‐77964, potent MMP inhibitors have been designed and synthesized to append a boron‐rich carborane cluster by employing click chemistry to target tumor cells that are known to upregulate gelatinases. Docking against MMP‐2 suggests binding involving the hydroxamate zinc‐binding group, key H‐bonds by the sulfone moiety with the peptide backbone residues Leu82 and Leu83, and a hydrophobic interaction with the deep P1’ pocket. The more potent of the two triazole regioisomers exhibits an IC50 of 3.7 nM versus MMP‐2 and IC50 of 46 nM versus MMP‐9.


Phosphorylation Of Adp-Glucose Pyrophosphorylase During Wheat Seeds Development, Danisa M. L. Ferrero, Claudia V. Piattoni, Matías D. Asencion Diez, Bruno E. Rojas, Matías D. Hartman, Miguel A. Ballicora, Alberto A. Iglesias Jul 2020

Phosphorylation Of Adp-Glucose Pyrophosphorylase During Wheat Seeds Development, Danisa M. L. Ferrero, Claudia V. Piattoni, Matías D. Asencion Diez, Bruno E. Rojas, Matías D. Hartman, Miguel A. Ballicora, Alberto A. Iglesias

Chemistry: Faculty Publications and Other Works

Starch is the dominant reserve polysaccharide accumulated in the seed of grasses (like wheat). It is the most common carbohydrate in the human diet and a material applied to the bioplastics and biofuels industry. Hence, the complete understanding of starch metabolism is critical to design rational strategies to improve its allocation in plant reserve tissues. ADP-glucose pyrophosphorylase (ADP-Glc PPase) catalyzes the key (regulated) step in the synthetic starch pathway. The enzyme comprises a small (S) and a large (L) subunit forming an S2L2 heterotetramer, which is allosterically regulated by orthophosphate, fructose-6P, and 3P-glycerate. ADP-Glc PPase was found in a phosphorylated …


Structural Basis For The Hydrolytic Dehalogenation Of The Fungicide Chlorothalonil, Daniel S. Catlin, Xinhang Yang, Brian Bennett, Richard C. Holz, Dali Liu Jun 2020

Structural Basis For The Hydrolytic Dehalogenation Of The Fungicide Chlorothalonil, Daniel S. Catlin, Xinhang Yang, Brian Bennett, Richard C. Holz, Dali Liu

Chemistry: Faculty Publications and Other Works

Cleavage of aromatic carbon–chlorine bonds is critical for the degradation of toxic industrial compounds. Here, we solved the X-ray crystal structure of chlorothalonil dehalogenase (Chd) from Pseudomonas sp. CTN-3, with 15 of its N-terminal residues truncated (ChdT), using single-wavelength anomalous dispersion refined to 1.96 Å resolution. Chd has low sequence identity (<15%) compared with all other proteins whose structures are currently available, and to the best of our knowledge, we present the first structure of a Zn(II)-dependent aromatic dehalogenase that does not require a coenzyme. ChdT forms a “head-to-tail” homodimer, formed between two α-helices from each monomer, with three Zn(II)-binding sites, two of which occupy the active sites, whereas the third anchors a structural site at the homodimer interface. The catalytic Zn(II) ions are solvent-accessible via a large hydrophobic (8.5 × 17.8 Å) opening to bulk solvent and two hydrophilic branched channels. Each active-site Zn(II) ion resides in a distorted trigonal bipyramid geometry with His117, His257, Asp116, Asn216, and a water/hydroxide as ligands. A conserved His residue, His114, is hydrogen-bonded to the Zn(II)-bound water/hydroxide and likely functions as the general acid-base. We examined substrate binding by docking chlorothalonil (2,4,5,6-tetrachloroisophtalonitrile, TPN) into the hydrophobic channel and observed that the most energetically favorable pose includes a TPN orientation that coordinates to the active-site Zn(II) ions via a CN and that maximizes a π–π interaction with Trp227. On the basis of these results, along with previously reported kinetics data, we propose a refined catalytic mechanism for Chd-mediated TPN dehalogenation.


Synthesis Of A Protected 2-Aminocyclobutanone As A Modular Transition State Synthon For Medicinal Chemistry, Thahani S. Habeeb Mohammad, Cory T. Reidl, Matthias Zeller, Daniel P. Becker Ph.D. Mar 2020

Synthesis Of A Protected 2-Aminocyclobutanone As A Modular Transition State Synthon For Medicinal Chemistry, Thahani S. Habeeb Mohammad, Cory T. Reidl, Matthias Zeller, Daniel P. Becker Ph.D.

Chemistry: Faculty Publications and Other Works

The hydrochloride salt of ɑ-aminocyclobutanone protected as its dimethyl acetal 2,2-dimethoxycyclobutan-1-aminium chloride (3) has been prepared as a modular synthon for convenient access to cyclobutanone-containing lead inhibitors of hydrolase enzymes including serine proteases and metalloproteases. Protected ɑ-aminocyclobutanone 3 was converted to representative amide and sulfonamide-functionalized 2-aminocyclobutanone derivatives. Reaction of the amino acetal 3 with phenyl isothiocyanate afforded the bicyclic urea 1-hydroxyl-2,4-diazabicyclo[3.2.0]heptane-3-thione (9) as confirmed by a single crystal X-ray structure.


Laser Surface Cleaning As A Novel Approach For Genesis Solar Wind Collectors, Martina Schmeling, I. V. Veryovkin, C. E. Tripa Jan 2020

Laser Surface Cleaning As A Novel Approach For Genesis Solar Wind Collectors, Martina Schmeling, I. V. Veryovkin, C. E. Tripa

Chemistry: Faculty Publications and Other Works

A new surface cleaning method utilizing lasers has been evaluated for its suitability to Genesis solar wind collectors


Metal Ions Impact On Shewanella Oneidensis Mr-1 Adhesion To Ito Electrode And The Enhancement Of Current Output, Aisha Awad Alshahrani Jan 2020

Metal Ions Impact On Shewanella Oneidensis Mr-1 Adhesion To Ito Electrode And The Enhancement Of Current Output, Aisha Awad Alshahrani

Dissertations

The goal of this study is to enhance the efficiency of bacterial extracellular electron transfer (EET) in Shewanella oneidensis MR-1 by enhancing adhesion to the electrode's surface. Our results clearly show a major difference in the attachment and behavior of Shewanella oneidensis MR-1 for Ca2+, Pb2+, Cd2+, and Mg2+, compared to the control. the final microbial coverage, as measured by confocal microscopy and cathodic peak charge in cyclic voltammetry (Qpc), increases with increasing metal ion concentrations. We found the cells attached to the electrode increased more with the addition of metal ion concentrations in the following order of metals: Ca2+ …


Optimization Of Microbial Fuel Cells, Norberto M. Gonzalez Jan 2020

Optimization Of Microbial Fuel Cells, Norberto M. Gonzalez

Dissertations

Optimization of microbial fuel cells is investigated by utilizing Shewanella oneidensis as a model microorganism. the microbe's ability to grow and use glucose as a carbon source is explored under varying oxygen environments through an offline PMP derivatization method and HPLC analysis. Shewanella growth and glucose utilization is enhanced under aerobic environments; however, under microaerobic environments the addition of ferric iron results in a faster exponential growth initialization. a flavin mononucleotide modified indium tin oxide electrode is prepared and characterized for its usefulness in microbial fuel cells by controlled potential electrolysis, cyclic voltammetry, and electrochemical impedance spectroscopy studies. the electrode …


Lewis Acid-Carbonyl Solution Interactions And Their Implications In Catalytic Systems, Carly Soren Hanson Jan 2020

Lewis Acid-Carbonyl Solution Interactions And Their Implications In Catalytic Systems, Carly Soren Hanson

Dissertations

The utilization of Lewis acids to activate substrates containing carbonyls is ubiquitous in organic synthetic methods. in order to facilitate the development of novel reaction pathways and understand existing methods, it is necessary to determine the solution interactions between Lewis acids and Lewis bases. Historically, the characterization of the interactions of Lewis pairs has relied on solid state infrared (IR) spectroscopy and X-ray crystallography, as well as in situ NMR. I have developed a method utilizing in situ IR spectroscopy and solution conductivity towards the identification of the solution structures formed when a range of carbonyl compounds are combined with …