Amino Acids, Peptides, and Proteins Commons^™

Antiphosphatidylserine/Prothrombin Antibodies In Childhood Sle Are Associated With Lupus Anticoagulant Positivity, S. Chugh, R. Pilania, A. Kler, C. Hans, Narender Kumar, S. Singh, J. Ahluwalia

School of Medicine Faculty Publications

ISTH 2023 Congress, June 24 - 28, 2023, Montreal, Canada

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 …

Purification And Biochemical Characterization Of The Dna Binding Domain Of The Nitrogenase Transcriptional Activator Nifa From Gluconacetobacter Diazotrophicus, Heidi G. Standke, Lois Kim, Cedric P. Owens

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

NifA is a σ⁵⁴ activator that turns on bacterial nitrogen fixation under reducing conditions and when fixed cellular nitrogen levels are low. The redox sensing mechanism in NifA is poorly understood. In α- and β-proteobacteria, redox sensing involves two pairs of Cys residues within and immediately following the protein’s central AAA⁺ domain. In this work, we examine if an additional Cys pair that is part of a C(X)5 C motif and located immediately upstream of the DNA binding domain of NifA from the α-proteobacterium Gluconacetobacter diazotrophicus (Gd) is involved in redox sensing. We hypothesize that the …

Characterization Of Epithelial Growth Factor Transcripts Identified In Crotalus Atrox Venom, Ivan Lopez, Ying Jia

Research Symposium

Epithelial Growth Factor (EGF) is the primary source in regeneration and stimulation of essential fibroblasts cells commonly found in epithelium. Studies have shown that snake venom components are becoming a growing factor in treating illnesses such as cancer, muscular dystrophy, chronic pain, blood pressure, blood clotting, etc. EGF in human cells contains a promising quaternary structure that can bind to snake venom metalloproteinases, proposing a means of activating biochemical responses through protein-protein interactions to regulate unwanted cellular functions. This supports promising research in achieving a greater understanding of regulation along cellular pathways through ligands, increasing the likelihood of targeting unwanted …

Differential Cortical Monoamines Release During Exercise In Rats Chronically Implanted With Microdialysis Probes, Christine G. Gerin

Research Symposium

Physical exercise is known to positively influence mood, to reduce anxiety and to improve reaction to stress. Cerebral monoaminergic systems are thought to underly the neurochemical influence of exercise on mood and behavior. We hypothesized that beneficial effects of exercise can be shown by variations of neurotransmitters release in the cerebral cortex. We aimed at demonstrating that there is a temporal relationship between release of plasma and cerebral monoamines (A, NA, 5-HT, DA) and spontaneous running exercise in rats. Ten Spague Dawley rats (250 g) were chronically implanted (for up to 39 days) with a left common carotid cannula and …

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 …

Protein S Antibody As An Adjunct Therapy For Hemophilia B, Hope P. Wilson, Aliyah Pierre, Ashley L. Paysse, Narender Kumar, Brian C. Cooley, Pratyadipta Rudra, Adrianne W. Dorsey, Diana Polania-Villanueva, Sabyasachi Chatterjee, Maissaa Janbain, Maria C. Velez, Rinku Majumder

School of Medicine Faculty Publications

ABSTRACT: Hemophilia B (HB) is caused by an inherited deficiency of plasma coagulation factor IX (FIX). Approximately 60% of pediatric patients with HB possess a severe form of FIX deficiency (< 1% FIX activity). Treatment typically requires replacement therapy through the administration of FIX. However, exogenous FIX has a limited functional half-life, and the natural anticoagulant protein S (PS) inhibits activated FIX (FIXa). PS ultimately limits thrombin formation, which limits plasma coagulation. This regulation of FIXa activity by PS led us to test whether inhibiting PS would extend the functional half-life of FIX and thereby prolong FIX-based HB therapy. We assayed clotting times and thrombin generation to measure the efficacy of a PS antibody for increasing FIX activity in commercially obtained plasma and plasma from pediatric patients with HB. We included 11 pediatric patients who lacked additional comorbidities and coagulopathies. In vivo, we assessed thrombus formation in HB mice in the presence of the FIXa ± PS antibody. We found an accelerated rate of clotting in the presence of PS antibody. Similarly, the peak thrombin formed was significantly greater in the presence of the PS antibody, even in plasma from patients with severe HB. Furthermore, HB mice injected with PS antibody and FIX had a 4.5-fold higher accumulation of fibrin at the thrombus induction site compared with mice injected with FIX alone. Our findings imply that a PS antibody would be a valuable adjunct to increase the effectiveness of FIX replacement therapy in pediatric patients who have mild, moderate, and severe HB.

The Discovery, Characterization, And Engineering Of Autolytic Enzymes As Antimicrobials, Jacob M. Furlon

Dartmouth College Ph.D Dissertations

In an age of rising levels of antibiotic resistance, we are quickly running out of tools to address some of the most virulent and widespread infectious bacteria. One group of enzymes that show significant potential for use as next-generation antibiotics are antimicrobial peptidoglycan hydrolases, often referred to as lysins. These enzymes are responsible for the breakdown of peptidoglycan within the bacterial cell wall, and, when exogenously applied, can result in dramatic destabilization of the cell wall leading to rapid lysis of the bacteria. While phage endolysins have been widely investigated as potential antimicrobials, the therapeutic potential of endogenous autolysins from …

Structural Features Of Thyroglobulin Linked To Protein Trafficking, Cintia E. Citterio, Kookjoo Kim, Bhavana Rajesh, Kevin Pena, Oliver Biggs Clark, Peter Arvan

Pharmacy Faculty Articles and Research

Thyroglobulin must pass endoplasmic reticulum (ER) quality control to become secreted for thyroid hormone synthesis. Defective thyroglobulin, blocked in trafficking, can cause hypothyroidism. Thyroglobulin is a large protein (~2750 residues) spanning regions I–II–III plus a C-terminal cholinesterase-like domain. The cholinesterase-like domain functions as an intramolecular chaperone for regions I–II–III, but the folding pathway leading to successful thyroglobulin trafficking remains largely unknown. Here, informed by the recent three-dimensional structure of thyroglobulin as determined by cryo-electron microscopy, we have bioengineered three novel classes of mutants yielding three entirely distinct quality control phenotypes. Specifically, upon expressing recombinant thyroglobulin, we find that first, mutations …

Her3 Functions As An Effective Therapeutic Target In Triple Negative Breast Cancer To Potentiate The Antitumor Activity Of Gefitinib And Paclitaxel, Hui Lyu, Fei Shen, Sanbao Ruan, Congcong Tan, Jundong Zhou, Ann D. Thor, Bolin Liu

School of Medicine Faculty Publications

Background: Triple negative breast cancer (TNBC) represents a significant clinical challenge. Chemotherapy remains the mainstay for a large part of TNBC patients, whereas drug resistance and tumor recurrence frequently occur. It is in urgent need to identify novel molecular targets for TNBC and develop effective therapy against the aggressive disease. Methods: Immunohistochemistry was performed to examine the expression of HER3 in TNBC samples. Western blots were used to assess protein expression and activation. Cell proliferation and viability were determined by cell growth (MTS) assays. TCGA databases were analyzed to correlate HER3 mRNA expression with the clinical outcomes of TNBC patients. …

Nanodiscs: A Novel Approach To The Study Of The Methionine Abc Transporter System, Michael T. Winslow

Master's Theses

Membrane transporter proteins play the vital role of moving compounds in and out of the cell and are essential for all living organisms. ATP Binding Cassette (ABC) family transporters function both as importers and exporters in prokaryotes. MetNI is an E. coli Type I ABC transporter responsible for the uptake of methionine into the cytosol from the cell periplasmic space through the cell membrane to maintain intracellular methionine pools. ABC transporters, like other membrane proteins, are most often mechanistically and structurally studied in vitro, solubilized by detergents. However, detergent micelles may affect the conformational changes of membrane proteins relative to …

Additive Effects Of Cyclic Peptide [R4w4] When Added Alongside Azithromycin And Rifampicin Against Mycobacterium Avium Infection, Melissa Kelley, Kayvan Sasaninia, Arbi Abnousian, Ali Badaoui, James Owens, Abrianna Beever, Nala Kachour, Rakesh Kumar Tiwari, Vishwanath Venketaraman

Pharmacy Faculty Articles and Research

Mycobacterium avium (M. avium), a type of nontuberculous mycobacteria (NTM), poses a risk for pulmonary infections and disseminated infections in immunocompromised individuals. Conventional treatment consists of a 12-month regimen of the first-line antibiotics rifampicin and azithromycin. However, the treatment duration and low antibiotic tolerability present challenges in the treatment of M. avium infection. Furthermore, the emergence of multidrug-resistant mycobacterium strains prompts a need for novel treatments against M. avium infection. This study aims to test the efficacy of a novel antimicrobial peptide, cyclic [R4W4], alongside the first-line antibiotics azithromycin and rifampicin in reducing M. avium survival. Colony-forming unit (CFU) …

Probing Conformational Landscapes Of Binding And Allostery In The Sars-Cov-2 Omicron Variant Complexes Using Microsecond Atomistic Simulations And Perturbation-Based Profiling Approaches: Hidden Role Of Omicron Mutations As Modulators Of Allosteric Signaling And Epistatic Relationships, Gennady M. Verkhivker, Mohammed Alshahrani, Grace Gupta, Sian Xiao, Peng Tao

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this study, we systematically examine the conformational dynamics, binding and allosteric communications in the Omicron BA.1, BA.2, BA.3 and BA.4/BA.5 spike protein complexes with the ACE2 host receptor using molecular dynamics simulations and perturbation-based network profiling approaches. Microsecond atomistic simulations provided a detailed characterization of the conformational landscapes and revealed the increased thermodynamic stabilization of the BA.2 variant which can be contrasted with the BA.4/BA.5 variants inducing a significant mobility of the complexes. Using the dynamics-based mutational scanning of spike residues, we identified structural stability and binding affinity hotspots in the Omicron complexes. Perturbation response scanning and network-based mutational …

Α7 Nicotinic Acetylcholine Receptor Interaction With G Proteins In Breast Cancer Cell Proliferation, Motility, And Calcium Signaling, Murat Oz, Justin R. King, Keun-Hang Susan Yang, Sarah Khushaish, Yulia Tchugunova, Maitham A. Khajah, Yunus A. Luqmani, Nadine Kabbani

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Chronic smoking is a primary risk factor for breast cancer due to the presence of various toxins and carcinogens within tobacco products. Nicotine is the primary addictive component of tobacco products and has been shown to promote breast cancer cell proliferation and metastases. Nicotine activates nicotinic acetylcholine receptors (nAChRs) that are expressed in cancer cell lines. Here, we examine the role of the α7 nAChR in coupling to heterotrimeric G proteins within breast cancer MCF-7 cells. Pharmacological activation of the α7 nAChR using choline or nicotine was found to increase proliferation, motility, and calcium signaling in MCF-7 cells. This effect …

Targeting Mcl-1 By A Small Molecule Nsc260594 For Triple-Negative Breast Cancer Therapy, Shengli Dong, Margarite D. Matossian, Hassan Yousefi, Maninder Khosla, Bridgette M. Collins-Burow, Matthew E. Burow, Suresh K. Alahari

School of Graduate Studies Faculty Publications

Triple-negative breast cancers (TNBCs) are aggressive forms of breast cancer and tend to grow and spread more quickly than most other types of breast cancer. TNBCs can neither be targeted by hormonal therapies nor the antibody trastuzumab that targets the HER2 protein. There are urgent unmet medical needs to develop targeted drugs for TNBCs. We identified a small molecule NSC260594 from the NCI diversity set IV compound library. NSC260594 exhibited dramatic cytotoxicity in multiple TNBCs in a dose-and time-dependent manner. NSC260594 inhibited the Myeloid cell leukemia-1 (Mcl-1) expression through downregulation of Wnt signaling proteins. Consistent with this, NSC260594 treatment increased …

The Structural Characterization And Bioactivity Assessment Of Nonspecific Lipid Transfer Protein 1 (Nsltp1) From Caraway (Carum Carvi) Seeds, Taibah Aldakhil, Saud O. Alshammari, Bushra Siraj, Bishoy El-Aarag, Shamshad Zarina, David Salehi, Aftab Ahmed

Pharmacy Faculty Articles and Research

Background

Carum carvi (caraway) of the Apiaceae family has been used in many cultures as a cooking spice and part of the folk medicine. Previous reports primarily focus on the medicinal properties of caraway seed essential oil and the whole seeds extract. However, no effort has been made to study caraway proteins and their potential pharmacological properties, including nonspecific lipid transfer protein (nsLTP), necessitating further research. The current study aimed to characterize nonspecific lipid transfer protein 1 (nsLTP1) from caraway seed, determine its three-dimensional structure, and analyze protein–ligand complex interactions through docking studies. We also evaluated nsLTP1 in vitro cytotoxic …

High Glucose-Upregulated Pd-L1 Expression Through Ras Signaling-Driven Downregulation Of Ptrh1 Leads To Suppression Of T Cell Cytotoxic Function In Tumor Environment, Chenggang Gao, Jiaoshun Chen, Jianwei Bai, Haoxiang Zhang, Yanyi Tao, Shihong Wu, Hehe Li, Heshui Wu, Qiang Shen, Tao Yin

School of Graduate Studies Faculty Publications

Background: Nearly 80% of patients with pancreatic cancer suffer from glucose intolerance or diabetes. Pancreatic cancer complicated by diabetes has a more immunosuppressive tumor microenvironment (TME) and is associated with a worse prognosis. The relationship between glucose metabolism and programmed cell death-Ligand 1 (PD-L1) is close and complex. It is important to explore the regulation of high glucose on PD-L1 expression in pancreatic cancer and its effect on infiltrating immune effectors in the tumor microenvironment. Methods: Diabetic murine models (C57BL/6) were used to reveal different immune landscape in euglycemic and hyperglycemic pancreatic tumor microenvironment. Bioinformatics, WB, iRIP [Improved RNA Binding …

Cancer Cell-Specific Cgas/Sting Signaling Pathway In The Era Of Advancing Cancer Cell Biology, Vijay Kumar, Caitlin Bauer, John H. Stewart

School of Graduate Studies Faculty Publications

Pattern-recognition receptors (PRRs) are critical to recognizing endogenous and exogenous threats to mount a protective proinflammatory innate immune response. PRRs may be located on the outer cell membrane, cytosol, and nucleus. The cGAS/STING signaling pathway is a cytosolic PRR system. Notably, cGAS is also present in the nucleus. The cGAS-mediated recognition of cytosolic dsDNA and its cleavage into cGAMP activates STING. Furthermore, STING activation through its downstream signaling triggers different interferon-stimulating genes (ISGs), initiating the release of type 1 interferons (IFNs) and NF-κB-mediated release of proinflammatory cytokines and molecules. Activating cGAS/STING generates type 1 IFN, which may prevent cellular transformation …

Yes-Associated Protein-1 Overexpression In Ocular Surface Squamous Neoplasia; A Potential Diagnostic Marker And Therapeutic Target, Peter Julius, Stepfanie N. Siyumbwa, Fred Maate, Phyllis Moonga, Guobin Kang, Trevor Kaile, John T. West, Charles Wood, Peter C. Angeletti

School of Graduate Studies Faculty Publications

Yes-associated protein-1 (YAP-1) is a Hippo system transcription factor, which serves as an oncogene in squamous cell carcinoma, and several solid tumors when the Hippo pathway is dysregulated. Yet, the activity of YAP-1 in ocular surface squamous neoplasia (OSSN) has not been determined. Here, we investigate the relationship between YAP-1 overexpression and OSSN. Using a cross-sectional study design, we recruited 227 OSSN patients from the University Teaching Hospitals in Lusaka, Zambia. Immunohistochemistry was used to assess YAP-1 protein overexpression in tumor tissue relative to surrounding benign squamous epithelium. OSSN patient samples (preinvasive, n = 62, 27% and invasive, n = …

Enhancement Of Tki Sensitivity In Lung Adenocarcinoma Through M6a-Dependent Translational Repression Of Wnt Signaling By Circ-Fbxw7, Kai Li, Zi Yang Peng, Rui Wang, Xiang Li, Ning Du, Da Peng Liu, Jia Zhang, Yun Feng Zhang, Lei Ma, Ye Sun, Shou Ching Tang, Hong Ren, Yi Ping Yang, Xin Sun

School of Medicine Faculty Publications

Background: Tyrosine kinase inhibitors (TKIs) that specifically target mutational points in the EGFR gene have significantly reduced suffering and provided greater relief to patients with lung adenocarcinoma (LUAD). The third-generation EGFR-TKI, Osimertinib, has been successfully employed in clinical treatments to overcome resistance to both original and acquired T790M and L858R mutational points. Nevertheless, the issue of treatment failure response has emerged as an insurmountable problem. Methods: By employing a combination of multiple and integrated approaches, we successfully identified a distinct population within the tumor group that plays a significant role in carcinogenesis, resistance, and recurrence. Our research suggests that addressing …