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Full-Text Articles in Physical Sciences and Mathematics

Ribbon Α-Conotoxin Ktm Exhibits Potent Inhibition Of Nicotinic Acetylcholine Receptors, Leanna A. Marquart, Matthew W. Turner, Lisa R. Warner, Matthew D. King, James R. Groome, Owen M. Mcdougal Dec 2019

Ribbon Α-Conotoxin Ktm Exhibits Potent Inhibition Of Nicotinic Acetylcholine Receptors, Leanna A. Marquart, Matthew W. Turner, Lisa R. Warner, Matthew D. King, James R. Groome, Owen M. Mcdougal

Chemistry and Biochemistry Faculty Publications and Presentations

KTM is a 16 amino acid peptide with the sequence WCCSYPGCYWSSSKWC. Here, we present the nuclear magnetic resonance (NMR) structure and bioactivity of this rationally designed α-conotoxin (α-CTx) that demonstrates potent inhibition of rat α3β2-nicotinic acetylcholine receptors (rα3β2-nAChRs). Two bioassays were used to test the efficacy of KTM. First, a qualitative PC12 cell-based assay confirmed that KTM acts as a nAChR antagonist. Second, bioactivity evaluation by two-electrode voltage clamp electrophysiology was used to measure the inhibition of rα3β2-nAChRs by KTM (IC50 = 0.19 ± 0.02 nM), and inhibition of the same nAChR isoform by α-CTx MII (IC50 = …


Synthesis Of Novel Reiii And Rev Metallointercalator Complexes For Use As Dna Damage Probes, Eli Schwartz May 2019

Synthesis Of Novel Reiii And Rev Metallointercalator Complexes For Use As Dna Damage Probes, Eli Schwartz

Honors Program Theses and Projects

Cancer is a disease that affects millions around the globe. Treatments such as radiation and chemotherapy are often used to treat cancerous tumors, but are not 100% effective in curing the patient. Alternatively, some research groups have proposed the use of metallointercalators, metal complexes consisting of a rhodium, ruthenium, or iridium metal center with bidentate supporting ligands such as bipyridine and phenanthroline, or tridentate ligands such as terpyridine. The complexes also contain a bidentate intercalating group such as dipyridophenazine. These complexes possess the ability to directly bind to DNA through intercalation between the stacks of DNA base pairs, giving them …


Obscurin Is A Semi-Flexible Molecule In Solution, Jacob Whitley May 2019

Obscurin Is A Semi-Flexible Molecule In Solution, Jacob Whitley

Senior Honors Projects, 2010-2019

Obscurin, a giant modular cytoskeletal protein, is comprised mostly of tandem immunoglobulin-like (Ig-like) domains. This architecture allows obscurin to connect distal targets within the cell. The linkers connecting the Ig domains are usually short (3-4 residues). The physical effect arising from these short linkers is not known; such linkers may lead to a stiff elongated molecule or, conversely, may lead to a more compact and dynamic structure. In an effort to better understand how linkers affect obscurin flexibility, and to better understand the physical underpinnings of this flexibility, here we study the structure and dynamics of four representative sets of …


The Characterization Of A New Metabolite From A Trichodesmium Bloom, Kelly M. Mcmanus May 2019

The Characterization Of A New Metabolite From A Trichodesmium Bloom, Kelly M. Mcmanus

Senior Honors Projects

Our laboratory has been investigating blooms of Trichodesmium, a genus of ecologically important, nitrogen-fixing cyanobacteria, collected from Padre Island in the Gulf of Mexico. Trichodesmium species are an underexplored biological source of cyanobacteria – a taxa that has been shown to produce chemically diverse secondary metabolites. With our focus on the isolation and structure characterization of new bioactive marine natural products, our research group has discovered over 25 new-to-science compounds over the past three years from these blooms. UV and mass spectrometry-guided isolation of Trichodesmium chromatography fractions were utilized to isolate a new metabolite. Isolation of this metabolite was …


Nmr Metabolomics Protocols For Drug Discovery, Fatema Bhinderwala, Robert Powers Jan 2019

Nmr Metabolomics Protocols For Drug Discovery, Fatema Bhinderwala, Robert Powers

Chemistry Department: Faculty Publications

Drug discovery is an extremely difficult and challenging endeavor with a very high failure rate. The task of identifying a drug that is safe, selective and effective is a daunting proposition because disease biology is complex and highly variable across patients. Metabolomics enables the discovery of disease biomarkers, which provides insights into the molecular and metabolic basis of disease and may be used to assess treatment prognosis and outcome. In this regard, metabolomics has evolved to become an important component of the drug discovery process to resolve efficacy and toxicity issues, and as a tool for precision medicine. A detailed …


Palladium Complexes Bearing Κ²-N,N And Κ³-N,N,O Pendant Amine Bis(Phenolate) Ligands, Brendan J. Graziano, Eric M. Collins, Nathaniel C. Mccutcheon, Claire L. Griffith, Nicole M. Braunscheidel, Trilisa M. Perrine, Bradley M. Wile Jan 2019

Palladium Complexes Bearing Κ²-N,N And Κ³-N,N,O Pendant Amine Bis(Phenolate) Ligands, Brendan J. Graziano, Eric M. Collins, Nathaniel C. Mccutcheon, Claire L. Griffith, Nicole M. Braunscheidel, Trilisa M. Perrine, Bradley M. Wile

Chemistry and Biochemistry Faculty Scholarship

The synthesis and characterization of ten new palladium(II) amine bis(phenolate) complexes is reported. Solution and single-crystal X-ray diffraction studies reveal the presence of both κ2-N,N and κ3-N,N,O binding modes in these square planar complexes. For complexes with sterically less demanding phenolate donors, addition of external acidic or basic reagents allows for the selective masking of a coordination site at Pd. Complexes bearing bulky cumyl substituents on phenolate donors exhibited unusual 1H NMR spectroscopic features that are consistent with an anagostic interaction with the palladium center. Computational analysis …


Structural Basis Of 7sk Rna 5′ Γ-Phosphate Methylation And Retention By Mepce, Yuan Yang, Catherine D. Eichhorn, Yaqiang Wang, Duilio Cascio, Juli Feigon Jan 2019

Structural Basis Of 7sk Rna 5′ Γ-Phosphate Methylation And Retention By Mepce, Yuan Yang, Catherine D. Eichhorn, Yaqiang Wang, Duilio Cascio, Juli Feigon

Chemistry Department: Faculty Publications

Among RNA 5′-cap structures, γ-phosphate monomethylation is unique to a small subset of noncoding RNAs, 7SK and U6 in humans. 7SK is capped by methylphosphate capping enzyme (MePCE), which has a second non-enzymatic role as a core component of the 7SK RNP that is an essential regulator of RNA transcription. We report 2.0 and 2.1 Å X-ray crystal structures of human MePCE methyltransferase domain bound to S-adenosylhomocysteine (SAH) and uncapped or capped 7SK substrates, respectively. 7SK recognition is achieved by protein contacts to a 5′ hairpin-single-stranded RNA region, explaining MePCE specificity for 7SK and U6. The structures reveal SAH and …


The Benefit Of Precise Chemical Shift And Concentration Referencing In Nmr Applications, Ming Huang Jan 2019

The Benefit Of Precise Chemical Shift And Concentration Referencing In Nmr Applications, Ming Huang

Doctoral Dissertations

“In Nuclear Magnetic Resonance (NMR) spectroscopy, the chemical shift and intensity of NMR signals provide critical information about a sample's molecular structure, reaction conditions, and material properties. For the precise determination of structures and properties, it is critical to know sample or reaction conditions such as temperature, pH, concentration, or absolute amount of material. Chemical-shift and signal-intensity calibrations play a key role for extracting the maximum amount of information from NMR experiments. In this dissertation, internal and external reference standards are used to calibrate NMR spectra with respect to chemical shift and signal intensity. Sealed capillary tubes filled with specific …


Conformational Flexibility In The Enterovirus Rna Replication Platform, Meghan S. Warden, Kai Cai, Gabriel Cornilescu, Jordan E. Burke, Komala Ponniah, Samuel E. Butcher, Steven M. Pascal Jan 2019

Conformational Flexibility In The Enterovirus Rna Replication Platform, Meghan S. Warden, Kai Cai, Gabriel Cornilescu, Jordan E. Burke, Komala Ponniah, Samuel E. Butcher, Steven M. Pascal

Chemistry & Biochemistry Faculty Publications

A presumed RNA cloverleaf (5′CL), located at the 5′-most end of the noncoding region of the enterovirus genome, is the primary established site for initiation of genomic replication. Stem–loop B (SLB) and stem–loop D (SLD), the two largest stem–loops within the 5′CL, serve as recognition sites for protein interactions that are essential for replication. Here we present the solution structure of rhinovirus serotype 14 5′CL using a combination of nuclear magnetic resonance spectroscopy and small-angle X-ray scattering. In the absence of magnesium, the structure adopts an open, somewhat extended conformation. In the presence of magnesium, the structure compacts, bringing SLB …


Modeling Chaperone-Substrate Interactions Of Alpha Crystallin From The Ocular Lens, Lisa Marie S. Ramirez Jan 2019

Modeling Chaperone-Substrate Interactions Of Alpha Crystallin From The Ocular Lens, Lisa Marie S. Ramirez

Legacy Theses & Dissertations (2009 - 2024)

The α-crystallins (αA- and αB-crystallin isoforms) from the ocular lens are small heat shock proteins and molecular chaperones, widely believed to play a significant role in protecting the lens from cataract. Mutations and modifications on human αA- and αB-crystallin (HAA and HAB, respectively) are linked to a variety of diseases, including cataract formation, neuropathological protein folding disorders, and many others. It is believed that HAA and HAB prevent the aggregation of other lens proteins. However, the structural and thermodynamic details of the chaperone-substrate (aka “client”) interaction are sparse. Therefore, the main objective of this dissertation is to reveal structural and …