Chemistry Commons^™

Bioinformatic And Biophysical Analyses Of Proteins, Jonathan Catazaro

Department of Chemistry: Dissertations, Theses, and Student Research

The prevailing dogma in structural genomics is the existence of a strong correlation between protein sequence, structure, and biological function. Proteins with high sequence similarity typically have a similar, if not the same, structure and function. In many cases this logic can fail due to distantly related proteins having very low sequence similarity, a lack of a representative structure, structural novelty, or the absence of a characterized function. Further, the paradigm fails to account for dynamics, which have a significant effect on structural stability and enzymatic efficacy.

Nuclear magnetic resonance (NMR) spectroscopy is uniquely capable of solving the structure, assisting …

Hydroformylation And Aldehyde-Water Shift Catalysis By Dirhodium Tetraphosphine Complexes, Marshall Douglas Moulis

LSU Doctoral Dissertations

The use of a unique tetraphosphine ligand (et,ph-P4) allows for the chelating of two rhodium centers to perform bimetallic coopertivity in hydroformylation reactions to better the yields the linear aldehyde product. The proposed catalyst is [Rh₂(μ-H)₂(CO)₄(rac-et,ph-P4)]²⁺ and has been studied by in situ FT-IR and NMR. When tested in a polar phasic acetone/water (30 % by vol.), the catalyst forms a monocationic system [Rh₂(μ-H)₂(CO)₄(rac-et,ph-P4)]⁺ that has an initial TOF of 26 min^-1, selectivity of 27:1 L:B, and low byproducts of …

Structure Of Porphyrin Tpps4 And Its Interaction With Metal Ions As Elucidated By 1h Nmr And Uv-Visible Spectra, Zhiyan Song, Adegboye Adeyemo, Jannie Baker, Shakeya Traylor, Marcia Lightfoot

Georgia Journal of Science

Porphyrins are a group of tetrapyrrole pigments. Physical and chemical properties of porphyrins are often related to their compositions and structures. We conducted ¹H solution NMR and UV-visible spectral analysis to characterize the structural feature of a water-soluble, synthetic porphyrin i.e. tetrakis (p-sulfonatophenyl) porphyrin, TPPS₄, and its interaction with different metal ions in aqueous solutions. The results indicate that tetrapyrrole and tetraphenyl rings in TPPS₄ molecule form a co-planar electron conjugation system; transition-metal ions show stronger binding capacity than alkali and alkali-earth metal ions; the relative stabilities of TPPS₄-metal ion complexes can be well …

The Effects Of Carrier Ligands On Cisplatin Binding To Cysteine And Methionine, Adam C.R Smith

Masters Theses & Specialist Projects

We have reacted several derivatives of the anticancer drug cisplatin with N-acetyl-Lcysteine (N-AcCys) and N-acetyl-L-methionine (N-AcMet), which are two of the primary amino acid targets of platinum. NMR spectroscopy was used to monitor the reactions and determine the effect the different ligands would have on the platinum reactivity. Several of the platinum compounds were tested at pH of 4 and 7, and with platinum:amino acid ratios of 1:1, 2:1 and 1:2. Competition reactions between cysteine and methionine were done to confirm which would react with the platinum compound first. [Pt(dien)(NO3)]+ reacts faster with methionine than with cysteine at both pH …

Alicyclic And Aromatic Carboxylic Acids In Soil Organic Matter: An Investigation Of Potential Origin And Association With Plutonium Using Advanced Analytical Techniques, Nicole Didonato

Chemistry & Biochemistry Theses & Dissertations

Carboxylic acids are a defining component of soil organic matter, responsible for many of the physical and chemical properties, including metal-organic matter interactions, which govern its role as an important constituent of soils. However, there is a shortage of detailed molecular level information regarding orientation and structural arrangement of carboxylic acids within soil organic matter. This dissertation utilizes electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS) as well as solid-state and multi-dimensional nuclear magnetic resonance (NMR) to investigate the molecular formula composition within several organic matter sources and the primary structures that feature carboxylic acids. Soil organic matter …

Reactivity Of Ketyl And Acetyl Radicals From Direct Solar Actinic Photolysis Of Aqueous Pyruvic Acid, Alexis J. Eugene, Marcelo I. Guzman

Chemistry Faculty Publications

The variable composition of secondary organic aerosols (SOA) contributes to the large uncertainty for predicting radiative forcing. A better understanding of the reaction mechanisms leading to aerosol formation such as for the photochemical reaction of aqueous pyruvic acid (PA) at λ ≥ 305 nm can contribute to constrain these uncertainties. Herein, the photochemistry of aqueous PA (5-300 mM) continuously sparged with air is re-examined in the laboratory under comparable irradiance at 38° N at noon on a summer day. Several analytical methods are employed to monitor the time series of the reaction, including (1) the derivatization of carbonyl (C═O) functional …

Solution Conformations Of Three Small Cluster Oligosaccharide Mimetics (Scom) From D-Glucosamine, D-Altrosamine, And (-)-Quinic Acid, Q. L. Nguyen, L. Olmstead, S. Bains, Andreas H. Franz

Andreas H. Franz

Three small cluster oligosaccharide mimetics were synthesized, and their CDCl3 solution conformations were determined with NMR experiments. In this paper, we confirmed conformational similarities in rings A and B in all three compounds, and we provide the overall solution geometries. In all cases, an unusual cyclohexane twist-boat conformation with longrange 4 J-(W)-coupling was observed. The origin of the bias towards the twist-boat was attributed primarily to the fused ring system between the cyclohexane ring and the dioxacyclopentane (acetal) including hydrogen bonding. Temperature-annealed molecular dynamics simulations complemented the NMR experiments and supported the overall assignment.

Metabolic Investigations Of The Molecular Mechanisms Associated With Parkinson’S Disease, Robert Powers, Shulei Lei, Annadurai Anandhan, Darrell D. Marshall, Bradley Worley, Ronald Cerny, Eric D. Dodds, Yuting Huang, Mihalis I. Panayiotidis, Aglaia Pappa, Rodrigo Franco

Robert Powers Publications

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by fibrillar cytoplasmic aggregates of α-synuclein (i.e., Lewy bodies) and the associated loss of dopaminergic cells in the substantia nigra. Mutations in genes such as α -synuclein (SNCA) account for only 10% of PD occurrences. Exposure to environmental toxicants including pesticides and metals (e.g., paraquat (PQ) and manganese (Mn)) is also recognized as an important PD risk factor. Thus, aging, genetic alterations, and environmental factors all contribute to the etiology of PD. In fact, both genetic and environmental factors are thought to interact in the promotion of idiopathic PD, but the mechanisms …

Structural Characterization Of The Interactions Of Nicotinamide And Analogs With Human Sirt6 By Saturation Transfer Difference (Std) Nmr And Site Directed Mutagenesis, Beatriz Elena Bolivar-Vega

Legacy Theses & Dissertations (2009 - 2024)

The allosteric regulation of SIRT6 by nicotinamide (NAM), along with the growing evidence of this enzyme's key role in the immune response, prompted the mechanistic study of SIRT6 inhibition by pyrazinamide (PZA) and analogs. In our current study, PZA, an analog of NAM, was revealed to have a modest modulatory effect on SIRT6, an enzyme that regulates the NF-κB signaling pathway at the transcriptional level (a relevant pathway to inflammation). Similarly, the analogs of PZA, 5-Cl PZA, 5-MeO PZA, and POA exhibited a modulatory effect against SIRT6 in our in vitro studies, enabling identification of a potential new target for …