Amino Acids, Peptides, and Proteins Commons^™

Analysis Of Ligand Bias In Functional Studies Involving The Allosteric Modulation Of G Protein- Coupled Receptors, Frederick J. Ehlert, Michael T. Griffin

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Introduction

The affinity constants of a ligand for active and inactive states of a receptor ultimately determine its capacity to activate downstream signaling events. In this report, we describe a reverse-engineering strategy for estimating these microscopic constants.

Methods

Our approach involves analyzing responses measured downstream in the signaling pathway of a G protein-coupled receptor under conditions of allosteric modulation and reduced receptor expression or partial receptor inactivation. The analysis also yields estimates of the isomerization constant of the unoccupied receptor, the sensitivity constant of the signaling pathway, and the more empirical parameters of the receptor population including the observed affinities …

Anti-Gd2 Etoposide-Loaded Immunoliposomes For The Treatment Of Gd2 Positive Tumors, Brandon S. Brown

Dissertations and Theses (Open Access)

Systemic chemotherapeutics remain the standard of care for most malignancies even though they frequently suffer from narrow therapeutic index, poor serum solubility, and off-target effects. Monoclonal antibodies that specifically bind antigens overexpressed on many tumors such as the ganglioside, GD2, can be conjugated to drug-loaded liposomes to create a targeted drug delivery system. In this study, we have encapsulated etoposide, a topoisomerase inhibitor effective against a wide range of cancers, in surface modified liposomes decorated with anti-GD2 antibodies. We characterized the properties of the liposomes using a variety of methods including dynamic light scattering, electron microscopy, and Fourier transformed infrared …

Phage Display Library Screening For Psa-/Lo Prostate Cancer Cell-Binding Peptides, John R. Moore

Dissertations and Theses (Open Access)

Prostate cancer (PCa) is one of the leading malignancies affecting men worldwide. Our lab focuses on understanding the molecular mechanisms underlying prostate carcinogenesis and developing therapeutics that target the cells responsible for driving PCa and mediating therapy resistance. My master thesis research employs a phage display library screening technology aiming to identify peptides that preferentially home in to undifferentiated PCa cells, which our lab has previously demonstrated to be intrinsically resistant to castration.

There is now evidence that a population of cells in PCa possesses characteristics associated with stem cells; these cells are referred to as cancer stem cells (CSCs). …

Sample Limited Characterization Of A Novel Disulfide- Rich Venom Peptide Toxin From Terebrid Marine Snail Terebra Variegata, Prachi Anand, Alexandre Grigoryan, Mohammed H. Bhuiyan, Beatrix Ueberheide, Victoria Russell, Jose Quiñonez, Patrick Moy, Brian T. Chait, Sébastien F. Poget, Mandë Holford

Publications and Research

Disulfide-rich peptide toxins found in the secretions of venomous organisms such as snakes, spiders, scorpions, leeches, and marine snails are highly efficient and effective tools for novel therapeutic drug development. Venom peptide toxins have been used extensively to characterize ion channels in the nervous system and platelet aggregation in haemostatic systems. A significant hurdle in characterizing disulfide-rich peptide toxins from venomous animals is obtaining significant quantities needed for sequence and structural analyses. Presented here is a strategy for the structural characterization of venom peptide toxins from sample limited (4 ng) specimens via direct mass spectrometry sequencing, chemical synthesis and NMR …

Mechanism Underlying Ikk Activation Mediated By The Linear Ubiquitin Chain Assembly Complex (Lubac), Hiroaki Fujita, Simin Rahighi, Mariko Akita, Ryuichi Kato, Yoshiteru Sasaki, Soichi Wakatsuki, Kazuhiro Iwai

Pharmacy Faculty Articles and Research

The linear ubiquitin chain assembly complex (LUBAC) ligase, consisting of HOIL-1L, HOIP, and SHARPIN, specifically generates linear polyubiquitin chains. LUBAC-mediated linear polyubiquitination has been implicated in NF-κB activation. NEMO, a component of the IκB kinase (IKK) complex, is a substrate of LUBAC, but the precise molecular mechanism underlying linear chain-mediated NF-κB activation has not been fully elucidated. Here, we demonstrate that linearly polyubiquitinated NEMO activates IKK more potently than unanchored linear chains. In mutational analyses based on the crystal structure of the complex between the HOIP NZF1 and NEMO CC2-LZ domains, which are involved in the HOIP-NEMO interaction, NEMO mutations …

Responsive Polymers For Biosensing And Protein Delivery, Molla R. Islam, Yongfeng Gao, Xue Li, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

In this feature article, we review some of the most recent advances in the field of materials chemistry for biosensing, disease diagnostics, and drug delivery. Our recent work on the development of responsive polymer-based platforms for biosensing and drug delivery will also be highlighted. This feature article is meant to outline the breadth of the utility of polymer-based materials for select applications, as well as their enormous potential impact on future technologies.

The Abcs Of The Ribosome, Kurt Fredrick, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

An ABC protein that binds the ribosomal exit site suggests a new mechanism for direct regulation of translation in response to changing ATP levels in the cell.

Protein Binding Drug-Drug Interaction Between Warfarin And Tizoxanide In Human Plasma, Eduard Mullokandov, Jennifer Ahn, Andrew Szalkiewicz, Mariana Babayeva

Touro College of Pharmacy (New York) Publications and Research

The goal of the in vitro research was to evaluate the potential for inhibition of warfarin protein binding by tizoxanide. Warfarin was of particular interest for the present investigation because it has been shown to be highly bound to plasma proteins and is a narrow therapeutic index drug. Tizoxanide is an active metabolite of an anti-infective prodrug nitazoxanide and also highly protein-bound medication. Both drugs are expected to be co-administered clinically. Protein binding of warfarin was investigated using a centrifugal ultrafiltration technique. Co-administration of tizoxanide significantly inhibited protein binding of warfarin for all concentrations tested. Tizoxanide increased free fraction (fu) …

Self-Assembly Of Peptides To Nanostructures, Dindyal Mandal, Amir Nasrolahi Shirazi, Keykavous Parang

Pharmacy Faculty Articles and Research

The formation of well-ordered nanostructures through self-assembly of diverse organic and inorganic building blocks has drawn much attention owing to their potential applications in biology and chemistry. Among all organic building blocks, peptides are one of the most promising platforms due to their biocompatibility, chemical diversity, and resemblance with proteins. Inspired from the protein assembly in biological systems, various self-assembled peptide structures have been constructed using several amino acids and sequences. This review focuses on this emerging area, the recent advances in peptide self-assembly, and formation of different nanostructures, such as tubular, fibers, vesicles, spherical, and rod coil structures. While …

Cxcr7 Expression Disrupts Endothelial Cell Homeostasis And Causes Ligand-Dependent Invasion, Jennifer Totonchy, Lisa Clepper, Kevin G. Phillips, Owen J. T. Mccarty, Ashlee V. Moses

Pharmacy Faculty Articles and Research

The homeostatic function of endothelial cells (EC ) is critical for a number of physiological processes including vascular integrity, immunity, and wound healing. Indeed, vascular abnormalities resulting from EC dysfunction contribute to the development and spread of malignancies. The alternative SDF-1/CXCL12 receptor CXCR7 is frequently and specifically highly expressed in tumor-associated vessels. In this study, we investigate whether CXCR7 contributes to vascular dysfunction by specifically examining the effect of CXCR7 expression on EC barrier function and motility. We demonstrate that CXCR7 expression in EC results in redistribution of CD31/PECAM-1 and loss of contact inhibition. Moreover, CXCR7+ EC are deficient in …

Leptin Regulates Cd16 Expression On Human Monocytes In A Sex-Specific Manner, Joseph G. Cannon, Gyanendra Sharma, Gloria Sloan, Christiana Dimitropoulou, R. Randall Baker, Andrew Mazzoli, Barbara Kraj, Anthony Mulloy, Miriam Cortez-Cooper

School of Medical Diagnostics & Translational Sciences Publications

Fat mass is linked mechanistically to the cardiovascular system through leptin, a 16 kDa protein produced primarily by adipocytes. In addition to increasing blood pressure via hypothalamic-sympathetic pathways, leptin stimulates monocyte migration, cytokine secretion, and other functions that contribute to atherosclerotic plaque development. These functions are also characteristics of CD16-positive monocytes that have been implicated in the clinical progression of atherosclerosis. This investigation sought to determine if leptin promoted the development of such CD16-positive monocytes. Cells from 45 healthy men and women with age ranging from 20 to 59 years were analyzed. Circulating numbers of CD14++16++ monocytes, which are primary …

Non-Raft Ac2 Defines A Camp Signaling Compartment That Selectively Regulates Il-6 Expression In Airway Smooth Muscle Cells, Amy S. Bogard, Anna V. Birg, Rennolds S. Ostrom

Pharmacy Faculty Articles and Research

Adenylyl cyclase (AC) isoforms differ in their tissue distribution, cellular localization, regulation, and protein interactions. Most cell types express multiple AC isoforms. We hypothesized that cAMP produced by different AC isoforms regulates unique cellular responses in human bronchial smooth muscle cells (BSMC). Overexpression of AC2, AC3, or AC6 had distinct effects on forskolin (Fsk)-induced expression of a number of known cAMP-responsive genes. These data show that different AC isoforms can differentially regulate gene expression. Most notable, overexpression and activation of AC2 enhanced interleukin 6 (IL-6) expression, but overexpression of AC3 or AC6 had no effect. IL-6 production by BSMC was …

Cyclic Peptide-Capped Gold Nanoparticles For Enhanced Sirna Delivery, Amir Nasrolahi Shirazi, Karissa L. Paquin, Niall G. Howlett, Dindyal Mandal, Keykavous Parang

Pharmacy Faculty Articles and Research

Previously, we have reported the synthesis of a homochiral L-cyclic peptide [WR]5 and its use for delivery of anti-HIV drugs and biomolecules. A physical mixture of HAuCl4 and the peptide generated peptide-capped gold nanoparticles. Here, [WR]5 and [WR]5-AuNPs were tested for their efficiency to deliver a small interfering RNA molecule (siRNA) in human cervix adenocarcinoma (HeLa) cells. Flow cytometry investigation revealed that the intracellular uptake of a fluorescence-labeled non-targeting siRNA (200 nM) was enhanced in the presence of [WR]5 and [WR]5-AuNPs by 2- and 3.8-fold when compared with that of siRNA alone after 24 h incubation. Comparative toxicity results showed …

Involvement Of Sigma-1 Receptors In The Antidepressant-Like Effects Of Dextromethorphan, Linda Nguyen, Matthew J. Robson, Jason R. Healy, Anna L. Scandinaro, Rae Reiko Matsumoto

Faculty Publications & Research of the TUC College of Pharmacy

Dextromethorphan is an antitussive with a high margin of safety that has been hypothesized to display rapid-acting antidepressant activity based on pharmacodynamic similarities to the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine. In addition to binding to NMDA receptors, dextromethorphan binds to sigma-1 (s1) receptors, which are believed to be protein targets for a potential new class of antidepressant medications. The purpose of this study was to determine whether dextromethorphan elicits antidepressant-like effects and the involvement of s1 receptors in mediating its antidepressant-like actions. The antidepressant-like effects of dextromethorphan were assessed in male, Swiss Webster mice using the forced swim test. Next, …

Cardiac Troponin Assessment Following Atrial Fibrillation Ablation: Implications For Chest Pain Evaluation, Jason C. Rubenstein, Jason T. Jacobson, Jeffrey J. Goldberger, Rod Passman, Alan H. Kadish, Michael H. Kim

Office of the President Publications and Research

Background: The range of elevation of troponin I (tI) that is within expected limits from left atrial radiofrequency ablation for atrial fibrillation (AF) is not well described, though such information may be of clinical value.

Objectives: Identify the expected range of tI values post-atrial fibrillation (AF) ablation.

Methods: 31 patients undergoing AF ablation had a single tI level drawn the day following the procedure. Clinical variables were also collected, such as ablation type and radiofrequency (RF) time.

Results: Paroxysmal AF was present in 23 patients, and 8 had chronic AF. The average RF time was 2627.8 …

Carbocyclodipeptides As Modified Nucleosides: Synthesis And Anti- Hiv Activities, Bhupender S. Chhikara, M. Sudershan Rao, V. Kameshwara Rao, Anil Kumar, Karen W. Buckheit, Robert W. Buckheit Jr., Keykavous Parang

Pharmacy Faculty Articles and Research

A new class of nucleoside analogues were synthesized using cyclic dipeptides and modified 2′-deoxyfuranoribose sugars to introduce flexibility by peptides in place of common nucleoside bases and to determine their biological properties. The synthesis was carried out by coupling of a protected ribose sugar with synthesized dipeptides in the presence of hexamethyldisilazane and trimethylsilyltriflate. The final products were characterized by NMR and high-resolution MS-TOF spectroscopy. The compounds were evaluated for anti-HIV activities. 1-(4-Azido-5-(hydroxymethyl)tetrahydrofuran-2-yl)-3,6-diisopropylpiperazine-2,5-dione (compound 14) containing 3- and 6-isopropyl groups in the base and 3′-azide (EC50 = 1.96 μmol/L) was the most potent compound among all of the synthesized analogs.

Alteration Of Host Cell Ubiquitination By The Intracellular Bacterial Pathogen Coxiella Burnetii, Lindsay Pritchett, Daniel E. Voth

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

The intracellular bacterial agent of Q fever, Coxiella burnetii, replicates within a phagolysosomelike parasitophorous vacuole (PV) in human macrophages and delivers effector proteins to the host cytosol via a Dot/Icm type IV secretion system (T4SS). The T4SS effectors are critical for PV formation and prevention of host cell death that allows sufficient time for bacterial replication. Recruitment of ubiquitin-related components to the C. burnetii PV is also predicted to be involved in PV formation and bacterial replication and is likely controlled by effector proteins. In this study, we assessed the role of the Dot/Icm T4SS in regulating ubiquitination by comparing …

Computational Modeling Of Allosteric Regulation In The Hsp90 Chaperones: A Statistical Ensemble Analysis Of Protein Structure Networks And Allosteric Communications, Kristin Blacklock, Gennady M. Verkhivker

Mathematics, Physics, and Computer Science Faculty Articles and Research

A fundamental role of the Hsp90 chaperone in regulating functional activity of diverse protein clients is essential for the integrity of signaling networks. In this work we have combined biophysical simulations of the Hsp90 crystal structures with the protein structure network analysis to characterize the statistical ensemble of allosteric interaction networks and communication pathways in the Hsp90 chaperones. We have found that principal structurally stable communities could be preserved during dynamic changes in the conformational ensemble. The dominant contribution of the inter-domain rigidity to the interaction networks has emerged as a common factor responsible for the thermodynamic stability of the …

Allosteric Regulation Of The Hsp90 Dynamics And Stability By Client Recruiter Cochaperones: Protein Structure Network Modeling, Kristin Blacklock, Gennady M. Verkhivker

Mathematics, Physics, and Computer Science Faculty Articles and Research

The fundamental role of the Hsp90 chaperone in supporting functional activity of diverse protein clients is anchored by specific cochaperones. A family of immune sensing client proteins is delivered to the Hsp90 system with the aid of cochaperones Sgt1 and Rar1 that act cooperatively with Hsp90 to form allosterically regulated dynamic complexes. In this work, functional dynamics and protein structure network modeling are combined to dissect molecular mechanisms of Hsp90 regulation by the client recruiter cochaperones. Dynamic signatures of the Hsp90-cochaperone complexes are manifested in differential modulation of the conformational mobility in the Hsp90 lid motif. Consistent with the experiments, …

Amphiphilic Triazolyl Peptides: Synthesis And Evaluation As Nanostructures, Naser Sayeh, Amir Nasrolahi Shirazi, Donghoon Oh, Jiadong Sun, David Rowley, Antara Banerjee, Arpita Yadav, Rakesh Tiwari, Keykavous Parang

Pharmacy Faculty Articles and Research

A new class of amphiphilic triazolyl peptides was designed and synthesized from peptide-based building blocks containing alkyne and azide functional groups namely linear (W(pG))3, cyclic[W(pG)]3, and Ac-K(N3)R-NH2,where W, R, K, and pG represent tryptophan, arginine, lysine, and propargylglycine residues, respectively. The linear (W(pG))3 and cyclic [W(pG)]3 peptides containing alkyne residues were conjugated with Ac-K(N3)R-NH2 functionalized with azide group through click chemistry in the presence of CuSO4.5H2O, Cu (powder), sodium ascorbate, and N,N-disopropylethylamine in methanol:water to afford amphiphilic triazolyl linear-linear (WG(triazole-KR-NH2))3 and cyclic-linear [WG(triazole-KR-NH2)]3 peptides, respectively. The secondary structures of both peptides were similar to a distorted α-helix as shown by …