Molecular Biology Commons^™

Biophysical Characterization Of Naturally Occurring Titin M10 Mutations, Michael William Rudloff

Senior Honors Projects, 2010-2019

The giant human muscle proteins titin and obscurin are important for sarcomeric organization, stretch response, and sarcomerogenesis in myofibrils. The extreme C-terminus of titin (the M10 domain) binds to the N-terminus of obscurin (the Ig1 domain) in the M-line, an interaction that is critical for sarcomere stability. The high-resolution structure of human M10 has been solved, along with M10 bound to one of its two known molecular targets, the Ig1 domain of obscurin-like protein. Multiple M10 mutations are linked to limb-girdle muscular dystrophy type 2J (LGMD2J) and tibial muscular dystrophy (TMD), however the effect of the M10 mutations on protein …

Atrial Fibrillation: Biophysics, Molecular Mechanisms, And Novel Therapies., Alexey V. Glukhov, Leonid V. Rosenshtraukh, Anamika Bhargava, Michele Miragoli, Bas J. D. Boukens

Anatomy and Regenerative Biology Faculty Publications

No abstract provided.

Elucidation Of A Novel Pathway In Staphylococcus Aureus: The Essential Site-Specific Processing Of Ribosomal Protein L27, Erin A. Wall

Theses and Dissertations

Ribosomal protein L27 is a component of the eubacterial large ribosomal subunit that has been shown to play a critical role in substrate stabilization during protein synthesis. This function is mediated by the L27 N-terminus, which protrudes into the peptidyl transferase center where it interacts with both A-site and P-site tRNAs as well as with 23S rRNA. We observed that L27 in S. aureus and other Firmicutes is encoded with a short N-terminal extension that is not present in most Gram-negative organisms, and is absent from mature ribosomes. The extension contains a conserved cleavage motif; nine N-terminal amino acids are …

Chemoenzymatic Studies To Enhance The Chemical Space Of Natural Products, Jhong-Min Chen

Theses and Dissertations--Pharmacy

Natural products provide some of the most potent anticancer agents and offer a template for new drug design or improvement with the advantage of an enormous chemical space. The overall goal of this thesis research is to enhance the chemical space of two natural products in order to generate novel drugs with better in vivo bioactivities than the original natural products.

Polycarcin V (PV) is a gilvocarcin-type antitumor agent with similar structure and comparable bioactivity with the principle compound of this group, gilvocarcin V (GV). Modest modifications of the polyketide-derived tetracyclic core of GV had been accomplished, but the most …

Physical Interactions Between Neuropilin And Vegfrs, Integrins In Regulating Endothelial Cell Functions, Xiaobo Li

Theses and Dissertations--Molecular and Cellular Biochemistry

The neuropilin (Nrp) family consists of multifunctional cell surface receptors with critical roles in a number of different cell and tissue types. A core aspect of Nrp function is ligand-dependent cellular adhesion and migration, where it controls the multistep process of cellular motility through integration of ligand binding, receptor coupling and signaling via the coordinated action of its extracellular and intracellular domains. While Nrp regulates cellular adhesion and motility in the cardiovascular and nervous systems under physiological conditions, the emerging pathological role of Nrp in tumor cell migration and metastasis has been identified and provides motivation for continued efforts toward …

Beryllium Nitrate Supports Fibroblast Migration As An Essential Component Of Skin And Limb Regeneration In Axolotls, Adam Boyd Cook

Theses and Dissertations--Biology

Tissue regeneration in salamanders is a robust process that is not easily interrupted or altered. Therefore, inhibiting regeneration provides a means to interrogate the underlying cellular and molecular mechanisms regulating this complex event. Here we show that application of a relatively low concentration of beryllium nitrate solution (100mM) causes a delay in skin regeneration and severely alters normal limb regeneration. We provide evidence showing a beryllium-induced reduction in dermal fibroblast migration in vivo and in vitro. We link this phenomenon to delayed regeneration of the skin and abnormal blastema formation resulting in limb patterning defects during regeneration. Though our …

Swarna Ramaswamy_Thesis, Swarna S. Ramaswamy

Dissertations and Theses (Open Access)

STRUCTURAL INVESTIGATIONS OF LIGAND GATED ION CHANNELS

Swarna Ramaswamy, B.S

Advisor: Vasanthi Jayaraman, Ph.D.

Ion channels form an integral part of membrane proteins. In the nervous system including the central and the peripheral nervous system, ligand gated ion channels form a very important part of intercellular communications. They receive chemical signals and convert them to electrical signal, mainly by allowing ion passage across the cell membrane. Ion passage also translates into downstream signaling events. Faithful translation of these signals and transmittance is crucial for several physiological functions, implying that irregular ion channel function could lead to serious consequences.

This thesis …

Numerical Simulations Of In Vitro Nanoparticle Toxicity – The Case Of Poly(Amido Amine) Dendrimers., Marcus Maher, Pratap Naha, Sourav Prasanna Mukherjee, Hugh Byrne

Articles

A phenomenological rate equation model is constructed to numerically simulate nanoparticle uptake and subsequent cellular response. Polyamidoamine dendrimers (generations 4-6) are modelled and the temporal evolution of the intracellular cascade of; increased levels of reactive oxygen species, intracellular antioxidant species, caspase activation, mitochondrial membrane potential decay, tumour necrosis factor and interleukin generation is simulated, based on experimental observations.

The dose and generation dependence of several of these response factors are seen to well represent experimental observations at a range of time points. The model indicates that variations between responses of different cell-lines, including murine macrophages, human keratinocytes and colon cells, …

Developing Crosslinking Constructs Of Protein Kinase R, Prisma E. Lopez

Honors Scholar Theses

Protein Kinase R (PKR) is a key component of the innate immune antiviral response. PKR is activated upon binding to dsRNA. However, recent studies have shown that PKR can also bind to and become activated by duplex RNAs containing complex secondary structure. The mechanism of PKR binding and activation by these RNAs is currently not known. The approach taken here to determine the mechanism of PKR binding by these RNAs is through the development of PKR constructs that are capable of covalently binding to RNAs. Constructs were created by site-specific incorporation of an unnatural, photoactivatable amino acid within PKR. These …

Mutagenesis Of 8-Oxoguanine Adjacent To An Abasic Site In Escherichia Coli Cells Proficient Or Deficient In Dna Polymerase Iv, Savas T. Tsikis

Honors Scholar Theses

It is well established that clustered DNA damages or multiply damaged sites (MDS) are the result of ionizing radiation and that they are characterized by an enhanced mutagenic potential. As a model MDS, we have evaluated the mutagenic and cytotoxic properties of the ubiquitous oxidative DNA damage 8-oxoguanine (G^8-oxo) adjacent to the abasic site lesion (Z) using a single stranded M13mp7L2 vector. The recombinant DNA was used to transform wild type E. coli strains and strains deficient in the translesion DNA polymerase of the Y-family, DNA polymerase IV, in the presence or absence of SOS induction. The percent …

Clpxp Modulates Cell Growth And Morphology In Cell Shape Mutants Of E.Coli, Ryann Murphy

Senior Honors Projects

ClpXP modulates cell growth and morphology in cell shape mutants of E. coli

Ryann Murphy¹ and Jodi L. Camberg¹

¹University of Rhode Island, Department of Cell and Molecular Biology, Kingston, RI, 02881

Penicillin Binding Proteins (PBPs) are a family of prokaryotic membrane proteins named for their propensity to bind the antibiotic penicillin and are involved in remodeling and deposition of peptidoglycan. In wild type Escherichia coli cells, the uniform rod shape is conserved across generations. E.coli cells containing multiple deletions of Low Molecular Weight (LMW) PBPs exhibit irregular shapes. LMW PBP5 (dacA) is a potential …

Understanding The Chemical Gymnastics Of Enzyme-Catalyzed 1’-1 And 1’-3 Triterpene Linkages, Stephen A. Bell

Theses and Dissertations--Plant and Soil Sciences

Squalene synthase (SS) is an essential enzyme in eukaryotic systems responsible for an important branch point in isoprenoid metabolism that leads to sterol formation. The mechanistic complexity of SS has made it a difficult enzyme to study. The green alga Botryococcus braunii race B possesses several squalene synthase-like (SSL) enzymes that afford a unique opportunity to study the complex mechanism of triterpene biosynthesis. SSL-1 catalyzes presqualene diphosphate (PSPP) formation, which can either be converted to squalene by SSL-2 or botryococcene by SSL-3. A rationally designed mutant study of B. braunii squalene synthase (BbSS) and SSL-3 was conducted to understand structure-function …

Molecular Mechanisms Of Neuropilin-Ligand Binding, Matthew W. Parker

Theses and Dissertations--Molecular and Cellular Biochemistry

Neuropilin (Nrp) is an essential cell surface receptor with dual functionality in the cardiovascular and nervous systems. The first identified Nrp-ligand family was the Semaphorin-3 (Sema3) family of axon repulsion molecules. Subsequently, Nrp was found to serve as a receptor for the vascular endothelial growth factor (VEGF) family of pro-angiogenic cytokines. In addition to its physiological role, VEGF signaling via Nrp directly contributes to cancer stemness, growth, and metastasis. Thus, the Nrp/VEGF signaling axis is a promising anti-cancer therapeutic target. Interestingly, it has recently been shown that Sema3 and VEGF are functionally opposed to one another, with Sema3 possessing potent …

Structural Mechanisms Of Glucan Phosphatase Activity In Starch Metabolism, David A. Meekins

Theses and Dissertations--Molecular and Cellular Biochemistry

Starch is a water-insoluble glucose biopolymer used as an energy cache in plants and is synthesized and degraded in a diurnal cycle. Reversible phosphorylation of starch granules regulates the solubility and, consequentially, the bioavailability of starch glucans to degradative enzymes. Glucan phosphatases release phosphate from starch glucans and their activity is essential to the proper diurnal metabolism of starch. Previously, the structural basis of glucan phosphatase activity was entirely unknown. The work in this dissertation outlines the structural mechanism of activity of two plant glucan phosphatases called Starch EXcess4 (SEX4) and Like Sex Four2 (LSF2). The crystal structures of SEX4 …

Stability Studies Of Membrane Proteins, Cui Ye

Theses and Dissertations--Chemistry

The World Health Organization has identified antimicrobial resistance as one of the top three threats to human health. Gram-negative bacteria such as Escherichia coli are intrinsically more resistant to antimicrobials. There are very few drugs either on the market or in the pharmaceutical pipeline targeting Gram-negative pathogens. Two mechanisms, the protection of the outer membrane and the active efflux by the multidrug transporters, play important roles in conferring multidrug resistance to Gram-negative bacteria. My work focuses on two main directions, each aligning with one of the known multidrug resistance mechanisms.

The first direction of my research is in the area …

Bayesian Reconstruction Of P(R) Directly From Two-Dimensional Detector Images Via A Markov Chain Monte Carlo Method, Sudeshna Paul, Alan M. Friedman, Chris Bailey-Kellogg, Bruce Craig

Dartmouth Scholarship

The interatomic distance distribution, P(r), is a valuable tool for evaluating the structure of a molecule in solution and represents the maximum structural information that can be derived from solution scattering data without further assumptions. Most current instrumentation for scattering experiments (typically CCD detectors) generates a finely pixelated two-dimensional image. In contin­uation of the standard practice with earlier one-dimensional detectors, these images are typically reduced to a one-dimensional profile of scattering inten­sities, I(q), by circular averaging of the two-dimensional image. Indirect Fourier transformation methods are then used to reconstruct P(r) from …

Investigating Therapeutic Options For Lafora Disease Using Structural Biology And Translational Methods, Amanda R. Sherwood

Theses and Dissertations--Molecular and Cellular Biochemistry

Lafora disease (LD) is a rare yet invariably fatal form of epilepsy characterized by progressive degeneration of the central nervous and motor systems and accumulation of insoluble glucans within cells. LD results from mutation of either the phosphatase laforin, an enzyme that dephosphorylates cellular glycogen, or the E3 ubiquitin ligase malin, the binding partner of laforin. Currently, there are no therapeutic options for LD, or reported methods by which the specific activity of glucan phosphatases such as laforin can be easily measured. To facilitate our translational studies, we developed an assay with which the glucan phosphatase activity of laforin as …

Dna-Binding Site Recognition By Bhlh And Mads-Domain Transcription Factors, Joshua R. Werkman

Theses and Dissertations--Plant and Soil Sciences

Herewithin, two transcription factor (TF) regulatory complexes were investigated. A bHLH–MYB–WDR (BMW) DNA-binding complex from maize was the first complex to be studied. R, a maize bHLH involved in the activation of genes in the anthocyanin pathway, had been characterized to indirectly bind DNA despite the presence of a functional DNA-binding domain. Findings presented here reveal that this is only partially correct. Direct DNA-binding by R was found to be dependent upon two distinct dimerization domains that function as a switch. This switch-like mechanism allows R to be repurposed for the activation of promoters of differing cis-element structure.

The …

Cloning, Expression, And Characterization Of Ara H 3, A Major Peanut Allergen, Cathryn E. Garvey

LSU New Orleans Theses and Dissertations

Abstract There are eight foods that contribute to food allergies in the western world and peanut is the most common. Currently, there are no medical treatments that can cure an individual of food allergy, so avoidance of the allergic food is the only option. In the United States, there are three immunodominant allergic proteins accountable for patient sensitization to peanut, Arachis hypogea 1, 2, and 3 (Ara h 1, Ara h 2, Ara h 3). Therefore, research into why peanuts are more allergic than other foods that have homologous proteins is critical and may be obtained by studying the structural …

Secondary Structure, A Missing Component Of Sequence- Based Minimotif Definitions, David P. Sargeant, Michael R. Gryk, Mark W. Maciejewsk, Vishal Thapar, Vamsi Kundeti, Sanguthevar Rajasekaran, Pedro Romero, Keith Dunker, Shun-Cheng Li, Tomonori Kaneko, Martin Schiller

Life Sciences Faculty Research

Minimotifs are short contiguous segments of proteins that have a known biological function. The hundreds of thousands of minimotifs discovered thus far are an important part of the theoretical understanding of the specificity of protein-protein interactions, posttranslational modifications, and signal transduction that occur in cells. However, a longstanding problem is that the different abstractions of the sequence definitions do not accurately capture the specificity, despite decades of effort by many labs. We present evidence that structure is an essential component of minimotif specificity, yet is not used in minimotif definitions. Our analysis of several known minimotifs as case studies, analysis …

Achieving High Accuracy Prediction Of Minimotifs, Tian Mi, Sanguthevar Rajasekaran, Jerlin Camilus Merlin, Michael R. Gryk, Martin Schiller

Life Sciences Faculty Research

The low complexity of minimotif patterns results in a high false-positive prediction rate, hampering protein function prediction. A multi-filter algorithm, trained and tested on a linear regression model, support vector machine model, and neural network model, using a large dataset of verified minimotifs, vastly improves minimotif prediction accuracy while generating few false positives. An optimal threshold for the best accuracy reaches an overall accuracy above 90%, while a stringent threshold for the best specificity generates less than 1% false positives or even no false positives and still produces more than 90% true positives for the linear regression and neural network …

Mutation And Complementation Of A Cellulose Synthase (Cesa) Gene, Ahmed Y. El-Araby

Senior Honors Projects

Cellulose is a carbohydrate polymer that is composed of repeating glucose subunits. Being the most abundant organic compound in the biosphere and comprising a large percentage of all plant biomass, cellulose is extremely plentiful and has a significant role in nature. Cellulose is present in plant cell walls, in commercial products such as those made from wood or cotton, and is of interest to the biofuel industry as a potential alternative fuel source. Although indigestible by humans, cellulose is nutritionally valuable, serving as a dietary fiber. Because of its ubiquity and importance in many areas, studying cellulose will prove to …

Conformational Changes In The Extracellular Domain Of Glutamate Receptors, Anu Rambhadran

Dissertations and Theses (Open Access)

The family of membrane protein called glutamate receptors play an important role in the central nervous system in mediating signaling between neurons. Glutamate receptors are involved in the elaborate game that nerve cells play with each other in order to control movement, memory, and learning.

Neurons achieve this communication by rapidly converting electrical signals into chemical signals and then converting them back into electrical signals. To propagate an electrical impulse, neurons in the brain launch bursts of neurotransmitter molecules like glutamate at the junction between neurons, called the synapse. Glutamate receptors are found lodged in the membranes of the post-synaptic …

Functional Studies Of Human Cellular Detoxification Enzymes, Melanie Neely Willis

Department of Biochemistry: Dissertations, Theses, and Student Research

Cellular detoxification allows for the maintenance of cellular homeostasis and prevention of abnormal cell growth by clearing harmful xenobiotics and endobiotics. After oxygenation by phase I enzymes, phase II enzymes such as glucuronosyltransferases and glutathione-s-transferases conjugate a small molecule to the compound, marking it for subsequent export. Many up-stream enzymes are also essential to cellular detoxification by supplying the small compounds for conjugation. These up-stream enzymes include UDP-glucose dehydrogenase, which synthesizes UDP-glucuronate, and glutamate cysteine ligase, which catalyzes the first and rate-limiting step in the synthesis of glutathione.
UDP-glucose dehydrogenase (UGDH) is an important enzyme in human development and in …

Scireader Enables Reading Of Medical Content With Instantaneous Definitions, Patrick R. Gradie, Megan Litster, Rinu Thomas, Jay Vyas, Martin Schiller

Life Sciences Faculty Research

Background

A major problem patients encounter when reading about health related issues is document interpretation, which limits reading comprehension and therefore negatively impacts health care. Currently, searching for medical definitions from an external source is time consuming, distracting, and negatively impacts reading comprehension and memory of the material.

Methods

SciReader was built as a Java application with a Flex-based front-end client. The dictionary used bySciReader was built by consolidating data from several sources and generating new definitions with a standardized syntax. The application was evaluated by measuring the percentage of words defined in different documents. A survey was used …

Mimosa: A System For Minimotif Annotation, Jay Vyas, Ronald J. Nowling, Thomas Meusburger, David P. Sargeant, Krishna Kadaveru, Michael R. Gryk, Vamsi Kundeti, Sanguthevar Rajasekaran, Martin Schiller

Life Sciences Faculty Research

BACKGROUND:

Minimotifs are short peptide sequences within one protein, which are recognized by other proteins or molecules. While there are now several minimotif databases, they are incomplete. There are reports of many minimotifs in the primary literature, which have yet to be annotated, while entirely novel minimotifs continue to be published on a weekly basis. Our recently proposed function and sequence syntax for minimotifs enables us to build a general tool that will facilitate structured annotation and management of minimotif data from the biomedical literature.

RESULTS:

We have built the MimoSA application for minimotif annotation. The application supports management of …

Partitioning Of Minimotifs Based On Function With Improved Prediction Accuracy, Sanguthevar Rajasekaran, Tian Mi, Jerlin Camilus Merlin, Aaron Oommen, Patrick R. Gradie, Martin R. Schiller

Life Sciences Faculty Research

Background

Minimotifs are short contiguous peptide sequences in proteins that are known to have a function in at least one other protein. One of the principal limitations in minimotif prediction is that false positives limit the usefulness of this approach. As a step toward resolving this problem we have built, implemented, and tested a new data-driven algorithm that reduces false-positive predictions.

Methodology/Principal Findings

Certain domains and minimotifs are known to be strongly associated with a known cellular process or molecular function. Therefore, we hypothesized that by restricting minimotif predictions to those where the minimotif containing protein and target protein have …

Venn, A Tool For Titrating Sequence Conservation Onto Protein Structures, Jay Vyas, Michael R. Gryk, Martin R. Schiller

Life Sciences Faculty Research

Residue conservation is an important, established method for inferring protein function, modularity and specificity. It is important to recognize that it is the 3D spatial orientation of residues that drives sequence conservation. Considering this, we have built a new computational tool, VENN that allows researchers to interactively and graphically titrate sequence homology onto surface representations of protein structures. Our proposed titration strategies reveal critical details that are not readily identified using other existing tools. Analyses of a bZIP transcription factor and receptor recognition of Fibroblast Growth Factor using VENN revealed key specificity determinants. Weblink: http://sbtools.uchc.edu/venn/.

A Proposed Syntax For Minimotif Semantics, Version 1., Jay Vyas, Ronald J. Nowling, Mark W. Maciejewski, Sanguthevar Rajasekaran, Michael R. Gryk, Martin R. Schiller

Life Sciences Faculty Research

BACKGROUND:

One of the most important developments in bioinformatics over the past few decades has been the observation that short linear peptide sequences (minimotifs) mediate many classes of cellular functions such as protein-protein interactions, molecular trafficking and post-translational modifications. As both the creators and curators of a database which catalogues minimotifs, Minimotif Miner, the authors have a unique perspective on the commonalities of the many functional roles of minimotifs. There is an obvious usefulness in standardizing functional annotations both in allowing for the facile exchange of data between various bioinformatics resources, as well as the internal clustering of sets of …

Geometric Build-Up Solutions For Protein Determination Via Distance Geometry, Robert Tucker Davis

Masters Theses & Specialist Projects

Proteins carry out an almost innumerable amount of biological processes that are absolutely necessary to life and as a result proteins and their structures are very often the objects of study in research. As such, this thesis will begin with a description of protein function and structure, followed by brief discussions of the two major experimental structure determination methods. Another problem that often arises in molecular modeling is referred to as the Molecular Distance Geometry Problem (MDGP). This problem seeks to find coordinates for the atoms of a protein or molecule when given only a set of pair-wise distances between …