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Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Group I Intron Internal Guide Sequence Binding Strength As A Component Of Ribozyme Network Formation, Elizabeth Satterwhite, Jessica Anne Mellor Yeates, Niles Lehman Sep 2016

Group I Intron Internal Guide Sequence Binding Strength As A Component Of Ribozyme Network Formation, Elizabeth Satterwhite, Jessica Anne Mellor Yeates, Niles Lehman

Chemistry Faculty Publications and Presentations

Origins-of-life research requires searching for a plausible transition from simple chemicals to larger macromolecules that can both hold information and catalyze their own production. We have previously shown that some group I intron ribozymes possess the ability to help synthesize other ribozyme genotypes by recombination reactions in small networks in an autocatalytic fashion. By simplifying these recombination reactions, using fluorescent anisotropy, we quantified the thermodynamic binding strength between two nucleotides of two group I intron RNA fragments for all 16 possible genotype combinations. We provide evidence that the binding strength (KD) between the 3-nucleotide internal guide sequence …


Insights From Molecular Dynamics On Substrate Binding And Effects Of Active Site Mutations In Delta1-Pyrroline-5-Carboxylate Dehydrogenase, Bogdan F. Ion, Mohamed M. Aboelnga, James W. Gauld Aug 2016

Insights From Molecular Dynamics On Substrate Binding And Effects Of Active Site Mutations In Delta1-Pyrroline-5-Carboxylate Dehydrogenase, Bogdan F. Ion, Mohamed M. Aboelnga, James W. Gauld

Chemistry and Biochemistry Publications

The NAD+-dependent enzyme, 1-pyrroline-5-carboxylate dehydrogenase (P5CDH), has an important role in proline and hydroxyproline catabolism for humans. Specifically, this aldehyde dehydrogenase is responsible for the oxidation of both L-glutamate- -semialdehyde (GSA) and 4-erythro-hydroxy-L-glutamate- -semialdehyde (4-OH-GSA) to their respective L-glutamate product forms. We have performed a detailed molecular dynamics (MD) study of both the reactant and product complex structures of P5CDH to gain insights into ligand binding (i.e., GSA, 4-OH-GSA, NAD+, GLU) in the active site. Moreover, our investigations were further extended to examine the structural impact of S352L, S352A, and E314A mutations on the deficiency in the P5CDH enzymatic activity. …


Computational Modeling Of Allosteric Stimulation Of Nipah Virus Host Binding Protein, Priyanka Dutta Jul 2016

Computational Modeling Of Allosteric Stimulation Of Nipah Virus Host Binding Protein, Priyanka Dutta

USF Tampa Graduate Theses and Dissertations

Nipah belongs to the family of paramyxoviruses that cause numerous fatal diseases in humans and farm animals. There are no FDA approved drugs for Nipah or any of the paramyxoviruses. Designing antiviral therapies that are more resistant to viral mutations require understanding of molecular details underlying infection. This dissertation focuses on obtaining molecular insights into the very first step of infection by Nipah. Such details, in fact, remain unknown for all paramyxoviruses. Infection begins with the allosteric stimulation of Nipah virus host binding protein by host cell receptors. Understanding molecular details of this stimulation process have been challenging mainly because, …


Stability Of Norwalk Virus Capsid Protein Interfaces Evaluated By In Silico Nanoindentation, Prakhar Bansal May 2016

Stability Of Norwalk Virus Capsid Protein Interfaces Evaluated By In Silico Nanoindentation, Prakhar Bansal

University Scholar Projects

Studying the mechanical properties of viral capsids can give several insights into not only the lifecycle of the virus, but also into potential drug targets to thwart the progression of viral infection. Nanoindentation using an atomic force microscope is a useful technique for determining structural properties of small molecules and particles, and is commonly used to study viral capsids. This technique utilizes the probe of the microscope to push down on the capsid and record the forces along the indentation path. We ran this experiment in silico where we simulated the nanoindentation of Norwalk virus capsids using molecular dynamics. Running …


Computational Investigations Into The Molecular Underpinnings Of Eyesight Signaling Pathways, Shaan Kamal May 2016

Computational Investigations Into The Molecular Underpinnings Of Eyesight Signaling Pathways, Shaan Kamal

University Scholar Projects

Phosphodiesterase 6 (PDE6) is a critical enzyme in the eyesight-signaling pathway. When activated, PDE6 hydrolyzes cGMP to GMP, which deactivates cGMP- gated ion channels, causing hyperpolarization of the cell and activating the sensory neurons responsible for vision. Within the PDE family, PDE6 is the only enzyme known to have an inhibitory subunit (PDE6-γ), which allows for the regulation of cGMP levels. When PDE6-γ is bound to PDE6, the enzyme is turned “off” and cannot catalyze cGMP. The α subunit of the G-protein transducin removes PDE6-γ and activates PDE6. PDE6 has proven problematic to isolate, making it difficult to study experimentally …


Studies Into The Allosteric Regulation Of Adp-Glucose Pyrophosphorylases, Benjamin Luke Hill Jan 2016

Studies Into The Allosteric Regulation Of Adp-Glucose Pyrophosphorylases, Benjamin Luke Hill

Dissertations

The synthesis of glycogen in bacteria and starch in plants is allosterically controlled by the production of ADP-glucose by ADP-glucose pyrophosphorylase. Using computational studies, site directed mutagenesis, and kinetic characterization, and protein crystallography we found a critical region for transmitting the allosteric signal in the Escherichia coli and A. tumefaciens ADP-glucose pyrophosphorylase. Molecular dynamics simulations and structural comparisons with other ADP-glucose pyrophosphorylases provided information to hypothesize communication pathways that link allosteric and active sites, and this was tested by site-directed mutagenesis and kinetic characterization of the mutant enzymes. In addition, the application of x-ray crystallography enabled the pinpointing of the …


A Five Residue Insertion Between Codons 28 And 29 Of The Hiv-1 Protease Gene Reduces The Replicative Capacity Of The Virus, Cathy Mcleod Jan 2016

A Five Residue Insertion Between Codons 28 And 29 Of The Hiv-1 Protease Gene Reduces The Replicative Capacity Of The Virus, Cathy Mcleod

Wayne State University Theses

HIV-1 protease (PR) is a 99 amino acid protein responsible for cleavage of the viral polyprotein. We have identified a novel clinical isolate, MDR/28, which contains a five residue insertion between codons 28 and 29 of a multi-drug resistant (MDR) PR. This clinical isolate displays reduced viral replicative capacity compared to the wild-type. As opposed to drug-resistance mutations, studies on insertions remain largely underrepresented in the literature, and the consequences of such insertions are largely unknown. To understand the mechanism leading to reduced replicative capacity, three PR models were created and subjected to 40ns molecular dynamics simulations: MDR/28, wild type, …