Structural Biology Commons^™

Molecular Characterization Of Nitrogenase Regulation In Methanosarcina Acetivorans, Melissa Chanderban

Graduate Theses and Dissertations

Nitrogenase is the metalloenzyme only found in bacteria and archaea that is essential for biological nitrogen fixation (diazotrophy), but it can also serve as a catalyst in biofuel production. All diazotrophs contain a molybdenum (Mo) nitrogenase, while some species contain additional alternative nitrogenases where either vanadium (V) or iron (Fe) replace Mo in the active site cofactor. Nitrogen fixation by bacteria has been extensively studied. The limited investigation of nitrogen fixation in methanogenic archaea (methanogens) indicates production of nitrogenase is simpler than in bacteria and methanogen nitrogenase has different biochemical properties. Thus, methanogen nitrogenases provide a promising alternative for genetic …

A Pipeline To Generate Deep Learning Surrogates Of Genome-Scale Metabolic Models, Achilles Rasquinha

School of Computing: Dissertations, Theses, and Student Research

Genome-Scale Metabolic Models (GEMMs) are powerful reconstructions of biological systems that help metabolic engineers understand and predict growth conditions subjected to various environmental factors around the cellular metabolism of an organism in observation, purely in silico. Applications of metabolic engineering range from perturbation analysis and drug-target discovery to predicting growth rates of biotechnologically important metabolites and reaction objectives within dierent single-cell and multi-cellular organism types. GEMMs use mathematical frameworks for quantitative estimations of flux distributions within metabolic networks. The reasons behind why an organism activates, stuns, or fluctuates between alternative pathways for growth and survival, however, remain relatively unknown. GEMMs …

Potential Use Of Proteolytic Bacteria Paenibacillus Dendritiformis (Bt7) Isolated From Batu Tannery Effluents For The Detergent Industry, Chandran Masi, Degafneh Tadesse, Abate Ayele

Karbala International Journal of Modern Science

This research was aimed at identifying a bacterium that can produce alkaline proteases. As a result, bacteria that produce proteases were isolated from Batu tannery effluents, tested for protease synthesis on skim milk agar plates, and validated with a protease assay. Microscopic and molecular phylogenetic analyses identified Paenibacillus dendritiformis (BT7) as the bacterial isolate with the highest alkaline protease production. The isolate's maximum enzyme production was obtained by 2% inoculum size, 40°C temperature, 9.0 pH, and a 48-hour incubation time with production media components such as glucose, casein, MgCl2, and 2% NaCl. The maximal enzyme activity was 270 U/mL under …

Seqcode: A Nomenclatural Code For Prokaryotes Described From Sequence Data, Brian P. Hedlund, Maria Chuvochina, Philip Hugenholtz, Konstantinos T. Konstantinidis, Alison E. Murray, Marike Palmer, Donovan H. Parks, Alexander J. Probst, Anna-Louise Reysenbach, Luis M. Rodriguez-R, Ramon Rossello-Mora, Iain C. Sutcliffe, Stephanus N. Venter, William B. Whitman

Life Sciences Faculty Research

Most prokaryotes are not available as pure cultures and therefore ineligible for naming under the rules and recommendations of the International Code of Nomenclature of Prokaryotes (ICNP). Here we summarize the development of the SeqCode, a code of nomenclature under which genome sequences serve as nomenclatural types. This code enables valid publication of names of prokaryotes based upon isolate genome, metagenome-assembled genome or single-amplified genome sequences. Otherwise, it is similar to the ICNP with regard to the formation of names and rules of priority. It operates through the SeqCode Registry (https://seqco.de/), a registration portal through which names and …

Examination Of The Time Delayed Induction Between Prior Encapsulation Of Catalytic Enzymes In P22 Virus-Like Particles, Andrea Hernandez Irias

Chemistry Theses

Protein cages found in nature have the ability to protect and develop new nanomaterials in order to enhance catalytic reactions. This is due to the ability of these organelle structures to mimic protein-based organelles such as Virus-Like Particles (VLPs). VLPs have the ability to not only resemble virus protein structures but to encapsulate enzymes while retaining their activity. This research examines the in vitro encapsulation withing the bacteriophage P22 derived VLP, and show that some enzymes may require a delay in encapsulation to allowed proper folding

and maturation before they can be encapsulated inside P22 as fully active enzymes. Exploring …

Helical Remodeling Augments 5-Lipoxygenase Activity In The Synthesis Of Proinflammatory Mediators, Eden M. Gallegos, Tanner D. Reed, Forge A. Mathes, Nelson V. Guevara, David B. Neau, Wei Huang, Marcia E. Newcomer, Nathaniel C. Gilbert

School of Medicine Faculty Publications

The synthesis of proinflammatory leukotrienes implicated in asthma, allergic rhinitis, and atherosclerosis is initiated by the enzyme 5-lipoxygenase (5-LOX). The crystal structure of human Stable-5-LOX revealed a conformation where the catalytic iron was inaccessible to bulk solvent as two aromatic residues on a conserved helix-α2 (Hα2) plugged the substrate access portal. Whether 5-LOX can also adopt a more open conformation has not been resolved. Here, we present a new conformation of 5-LOX where Hα2 adopts an elongated conformation equivalent to that described in other animal lipoxygenase structures. Our observation of the sigmoidal kinetic behavior of 5-LOX, which is indicative of …

Biochemical And Biophysical Characterization Of Replicative Helicase Loading By Vibrio Cholerae Dcia, Crystal Structure Of A Monoclonal Antibody Bound To A C-Terminal Fragment Of Ebna-1 From Epstein Barr Virus, Nicholas Gao

Dissertations, Theses, and Capstone Projects

DNA replication initiation is mediated by the binding of an initiator protein to genomic origins of replication to begin the process of loading replicative helicases onto the genome. The loading of the helicase requires the action of an accessory protein, named a “loader”. Studies on well-characterized loaders have outlined how the bacterial DnaB replicative helicase is loaded via mechanisms of “Ring-Breaking” by E. coli DnaC (EcDnaC)/protein P from bacteriophage lambda (LP) and “Ring-Making” by B. subtilis DnaI. Mounting evidence points to a recently discovered candidate loader, named DciA, that shows a more widespread distribution throughout bacteria than DnaC and DnaI …

Intermediates In Sars-Cov-2 Spike–Mediated Cell Entry, Tara C. Marcink, Thomas Kicmal, Emily Armbruster, Zhening Zhang, Gillian Zipursky, Kate L. Golub, Mohab Idris, Jonathan Khao, Jennifer Drew-Bear, Gael Mcgill, Tom Gallagher, Matteo Porotto, Amédée Des Georges, Anne Moscona

Advanced Science Research Center

SARS-CoV-2 cell entry is completed after viral spike (S) protein–mediated membrane fusion between viral and host cell membranes. Stable prefusion and postfusion S structures have been resolved by cryo–electron microscopy and cryo–electron tomography, but the refolding intermediates on the fusion pathway are transient and have not been examined. We used an antiviral lipopeptide entry inhibitor to arrest S protein refolding and thereby capture intermediates as S proteins interact with hACE2 and fusion-activating proteases on cell-derived target membranes. Cryo–electron tomography imaged both extended and partially folded intermediate states of S2, as well as a novel late-stage conformation on the pathway to …

Modeling Electrostatics In Molecular Biology And Its Relevance With Molecular Mechanisms Of Diseases, Mahesh Koirala

All Dissertations

Electrostatics plays an essential role in molecular biology. Modeling electrostatics in molecular biology is complicated due to the water phase, mobile ions, and irregularly shaped inhomogeneous biological macromolecules. This dissertation presents the popular DelPhi package that solves PBE and delivers the electrostatic potential distribution of biomolecules. We used the newly developed DelPhiForce steered Molecular Dynamics (DFMD) approach to model the binding of barstar to barnase and demonstrated that the first-principles method could also model the binding. This dissertation also reflects the use of existing computational approaches to model the effects of Single Amino Acid Variations (SAVs) to reveal molecular mechanisms …

Applications Of Nuclear Magnetic Resonance Spectroscopy: From Drug Discovery To Protein Structure And Dynamics., Mark Vincent C. Dela Cerna

Electronic Theses and Dissertations

The versatility of nuclear magnetic resonance (NMR) spectroscopy is apparent when presented with diverse applications to which it can contribute. Here, NMR is used i) as a screening/ validation tool for a drug discovery program targeting the Phosphatase of Regenerating Liver 3 (PRL3), ii) to characterize the conformational heterogeneity of p53 regulator, Murine Double Minute X (MDMX), and iii) to characterize the solution dynamics of guanosine monophosphate kinase (GMPK). Mounting evidence suggesting roles for PRL3 in oncogenesis and metastasis has catapulted it into prominence as a cancer drug target. Yet, despite significant efforts, there are no PRL3 small molecule inhibitors …

Mtorc1 And Mtorc2 Complexes Regulate The Untargeted Metabolomics And Amino Acid Metabolites Profile Through Mitochondrial Bioenergetic Functions In Pancreatic Beta Cells, Ghada A. Soliman, Rinat Abzalimov, Ye He

Advanced Science Research Center

Background: Pancreatic beta cells regulate bioenergetics efficiency and secret insulin in response to glucose and nutrient availability. The mechanistic Target of Rapamycin (mTOR) network orchestrates pancreatic progenitor cell growth and metabolism by nucleating two complexes, mTORC1 and mTORC2. Objective: To determine the impact of mTORC1/mTORC2 inhibition on amino acid metabolism in mouse pancreatic beta cells (Beta-TC-6 cells, ATCC-CRL-11506) using high-resolution metabolomics (HRM) and live-mitochondrial functions. Methods: Pancreatic beta TC-6 cells were incubated for 24 h with either: RapaLink-1 (RL); Torin-2 (T); rapamycin (R); metformin (M); a combination of RapaLink-1 and metformin (RLM); Torin-2 and metformin (TM); compared to the control. …

Cdc6 Is Sequentially Regulated By Pp2a-Cdc55, Cdc14, And Sic1 For Origin Licensing In S. Cerevisiae, Jasmin Philip

Dissertations, Theses, and Capstone Projects

Control of DNA replication is critical for progression of the cell cycle and genomic stability. Cyclin-dependent kinases (CDKs) coordinate numerous phosphorylation events to accomplish two biological tasks for all living organisms: DNA replication and cell division. One CDK, Cyclin-Cdc28, is responsible for cell cycle progression in budding yeast. DNA replication requires a stepwise assembly of the pre-replicative complex on DNA, including Orc1-6, Cdc6, Cdt1 and Mcm2-7, during M-G1 phase. Cdc6 contains eight Cdc28 consensus sites, SP or TP motifs. Clb5-Cdc28 phosphorylates Cdc6-T7 to recruit Cks1, the Cdc28 phospho-adaptor, for subsequent multisite phosphorylation during S phase. There are two phospho-degrons at …

A New Insight Into Fungal Cell Wall Architecture By Functional Genomics And Solid-State Nmr Along With Recent Advancements In Dynamic Nuclear Polarization For Analyzing Biomolecules, Arnab Chakraborty

LSU Master's Theses

This dissertation summarizes the findings related to the way by which supramolecular architecture of fungal cell wall changes with genetic mutation, dispensing genes responsible for biosynthesis of cell wall polysaccharides. This is necessary because without perfect picture of how supramolecular assembly changes with genetic mutation it is hard to assess new anti-fungal targets. Alongside this we have highlighted how recent advancement into Dynamic Nuclear Polarization (DNP) methods improved characterization of biomolecules both in case of labeled and unlabeled samples.

First study utilized Solid-state NMR (SSNMR) which is a non-destructive technique hence enabled us for the first time to deduce how …

Inferring Dynamics Of Biological Systems, Tracey G. Oellerich

Biology and Medicine Through Mathematics Conference

No abstract provided.

Assembly Of The Peripheral Arm Subunits Of Escherichia Coli Complex I And Analysis Of Clinical Mutations, Hind Alkhaldi

Biological Sciences Theses and Dissertations

Respiratory Complex I from E. coli is a proto-type of the mitochondrial enzyme, consisting of a 6-subunit peripheral arm (B-CD-E-F-G-I) and a 7-subunit membrane arm. When subunits E-F-G (N-module), were expressed alone they formed an active complex as determined by co-immunoprecipitation and native gel electrophoresis. When co-expressed with subunits B and CD, only a complex of E-F-G was found. When these five subunits were co-expressed with subunit I and two membrane subunits, A and H, a complex of B-CD-E-F-G-I was membrane-bound, constituting the N- and Q-modules. Assembly of Complex I was also followed by splitting the genes between two plasmids, …

Supertertiary Structural Dynamics Modulate Function In Postsynaptic Density Protein 95, George L. Hamilton Iii

All Dissertations

Proteins, RNA, and DNA serve as the primary sub-cellular machinery that give rise to the necessary functions of life. The long-standing paradigm has been that the structures of biomolecules, or the arrangement of the subunits that make up a biomolecule, determine biological function. However, biomolecules are not static objects. Instead, they often undergo structural rearrangements that are crucial to enabling and regulating their functions. In my thesis I present several studies of the interplay between the structures, dynamics, and functions of biomolecules that combine experimental fluorescence spectroscopy and computational methods to probe these systems at the single-molecule level. In particular, …

Modulation Of Kras Structure And Dynamics By Kras Ubiquitination And Membrane Depolarization, Vinay Nair

Dissertations and Theses (Open Access)

KRAS, a 21 kDa small GTPase protein, functions as a molecular switch playing a key role in regulating cell proliferation. Dysregulation of KRAS signaling by oncogenic mutations leads to uncontrolled cell proliferation, a hallmark of cancer cells. Attempts to therapeutically target oncogenic KRAS have led to limited success resulting in a need to identify new mechanisms to targeting KRAS. The interaction of KRAS with its regulators, effectors, and the membrane present one such avenue. In this study, we investigated how post-translational covalent and environmental modifications could modulate these interactions of KRAS. Using computational molecular dynamics simulations, nuclear magnetic resonance spectroscopy …

The Effect Of Age On The Mating Call Of The Tungara Frog, Zaizhen Xu

Pacific Undergraduate Research and Creativity Conference (PURCC)

No abstract provided.

Computational Investigations Into Binding Dynamics Of Tau Protein Antibodies: Using Machine Learning And Biophysical Models To Build A Better Reality, Katherine Lee

University Scholar Projects

Misregulation of post-translational modifications of microtubule-associated protein tau is implicated in several neurodegenerative diseases including Alzheimer’s disease. Hyperphosphorylation of tau promotes aggregation of tau monomers into filaments which are common in tau-associated pathologies. Therefore, tau is a promising target for therapeutics and diagnostics. Recently, high-affinity, high-specificity single-chain variable fragment (scFv) antibodies against pThr-231 tau were generated and the most promising variant (scFv 3.24) displayed 20-fold increased binding affinity to pThr-231 tau compared to the wild-type. The scFv 3.24 variant contained five point mutations, and intriguingly none were in the tau binding site. The increased affinity was hypothesized to occur due …

Design, Synthesis, And Analysis Of Paired Coiled-Coil Peptidic Molecular Building Blocks Used For Linearly Controlled Self-Assembly Of Α-Helical Coiled-Coil Heterodimer Peptide Pairs, Jason Distefano

Chemistry Theses

Molecular building blocks are fundamental to biological synthesis and processes and have been utilized in advanced materials, drugs and drug delivery systems, and biotechnology. Proteins have been used as molecular building blocks for the construction of complex, well-ordered structures. Coiled-coil protein domains are essential subunits used for the oligomerization of protein complexes, gene expression, and structural elements of biological materials. The synthesis and assembly of proteins utilizing coiled-coil motifs are of great scientific interest due to their potential applications in disease treatment, biomechanical motors, nanoscale delivery systems, etc. However, assembling protein complexes with specific morphology is still challenging because …