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Full-Text Articles in Physical Sciences and Mathematics

Metal Organic Frameworks (Mofs) Supported Single Atom Catalysts (Sacs) For Solar Fuel Conversion, Humphrey Chiromo Oct 2023

Metal Organic Frameworks (Mofs) Supported Single Atom Catalysts (Sacs) For Solar Fuel Conversion, Humphrey Chiromo

Dissertations (1934 -)

The continual reliance on non-renewable energy sources from fossil fuels to meet the world’s energy demand is causing serious environmental problems such as air pollution and global warming, hence there is a need of an alternative clean sustainable energy source. Exploration of clean sustainable renewable energies shows great promise to replace fossil fuels to meet global energy needs. Among the renewable energy sources, solar energy represents one of the most promising alternative energy sources due to its abundance and sustainability. However, the major challenge is the harvesting and storage of solar energy. One of the promising approaches to resolve these …


Photophysical And Photocatalytic Properties Of Covalent Organic Frameworks, Daniel Streater H. Jul 2023

Photophysical And Photocatalytic Properties Of Covalent Organic Frameworks, Daniel Streater H.

Dissertations (1934 -)

This dissertation is most interested in how a class of materials known as covalent organic frameworks (COFs) can be designed to capture photon energy to initiate chemical reactions. Different COF designs change how long the energy is held, how it migrates, and how it is dispersed – and these differences can be used to change their performance as artificial photosynthesis platforms. Thus, it is helpful to have an informative discussion about the processes behind natural photosynthesis, that is, nature’s light harvesting strategies and photocatalytic schemes (Section 1.2) and will lead into an introduction of COFs and why they possess unique …


Elucidating The Structure And Regulatory Interactions Of The Hotair Non-Coding Rna And The Bacterial Rnase P. Holoenzyme, Ainur Abzhanova Jul 2023

Elucidating The Structure And Regulatory Interactions Of The Hotair Non-Coding Rna And The Bacterial Rnase P. Holoenzyme, Ainur Abzhanova

Dissertations (1934 -)

RNA structures and RNA-protein interactions are studied as potential drug targets, biomarkers in cancer, and can be administered as vaccines. The cancer associated HOTAIR (HOX transcript antisense RNA) exists in higher vertebrates and interacts with chromatin remodeling enzymes. We examined the thermodynamic folding properties and structural propensity of the exonic regions of HOTAIR using biophysical methods and NMR spectroscopy. Different exons of HOTAIR contain variable degrees of structural heterogeneity. We identify one exonic region, exon 4, that adopts a stable and compact fold under low magnesium concentrations. Close agreement of NMR spectroscopy and chemical probing confirm conserved base pair interactions …


Exploring New Techniques For Precision Deuteration Of Alkenes And Alkynes, Zoua Pa Vang Apr 2023

Exploring New Techniques For Precision Deuteration Of Alkenes And Alkynes, Zoua Pa Vang

Dissertations (1934 -)

Deuterium labeled compounds are often utilized in chemical research as internal standards in mass spectrometry, to study reaction mechanisms and in the pharmaceutical industry to slow the rate of metabolism. With the increase interest for deuterium labeled molecules, there is a renewed interest in selective methods for the installation of deuterium atoms into small organic molecules. However, current methods to incorporate deuterium atoms into organic molecules can lead to isotopic mixtures such as isotopologues and isotopomers. These isotopic species are indistinguishable due to their similar physical properties, leading to inseparable products by common purification techniques. Furthermore, common spectroscopic techniques to …


Application Of Nanodisc Technology To A Membrane-Bound P450: Functional Studies And Resonance Raman Studies On Cyp51a1, Yuanqi Jing Oct 2022

Application Of Nanodisc Technology To A Membrane-Bound P450: Functional Studies And Resonance Raman Studies On Cyp51a1, Yuanqi Jing

Dissertations (1934 -)

Membrane-bound cytochrome P450s are highly insoluble and tend to form aggregations in aqueous solution due to its hydrophobic N-terminal transmembrane anchor. The traditional methodology of studying membrane-bound proteins depends on the use of detergent; however, detergent solubilization of membrane P450s does not satisfy many criteria of biochemical and biophysical studies on membrane proteins. A well-developed Nanodisc technology has been proven to be an extraordinarily efficient method of studying membrane-bound P450s. The human sterol 14-demethylases (CYP51A1) are membrane-bound P450 enzymes that catalyze oxidative removal of the C32 methyl group of lanosterol by first forming an alcohol, then an aldehyde, and finally …


Kinetics Of Isotope-Labeled Pathways In The Ozone Forming Recombination Reaction, Elizaveta Grushnikova Oct 2022

Kinetics Of Isotope-Labeled Pathways In The Ozone Forming Recombination Reaction, Elizaveta Grushnikova

Dissertations (1934 -)

The ozone layer in Earth’s atmosphere is unique and plays a vital role in the development of life. Studying the mechanism behind ozone formation helps us understand the development of our planet’s atmosphere. We focus here on the anomalous mass-independent isotope effect.1 In 1981, Mauersberger et al.2 performed an experiment using weather balloons, resulting in the discovery of the anomalous isotope effect for ozone formation. Since then, other chemists have continued to investigate the theory behind this phenomenon. To understand the nature of the isotope effect, we must consider all stages of ozone formation. The basic reaction for ozone formation …


Intrinsic Photodynamic Study On Photocatalytic Materials, Wenhui Hu Apr 2022

Intrinsic Photodynamic Study On Photocatalytic Materials, Wenhui Hu

Dissertations (1934 -)

To relieve the global energy crisis and environmental pollution caused by the combustion of traditional fossil fuels, developing an environmental-friendly renewable energy to replace fossil fuel is urgent. Among the possible energy sources, solar energy has attracted numerous attentions because of the abundant storage. However, it is challenging to efficiently utilize and store solar energy. One attractive strategy to address this challenge is to convert solar energy to fuel through artificial photosynthesis (e.g. photocatalytic water splitting to generate H2). A technologically significant solar-driven water splitting system requires an efficient photocatalytic system that can not only effectively harvest light but also …


Synthesis And Pharmacological Studies Of Ph-Sensitive, Allosteric, And Bivalent Ligands As Modulators Of Gpcrs, Ricardo Rosas Jr. Oct 2021

Synthesis And Pharmacological Studies Of Ph-Sensitive, Allosteric, And Bivalent Ligands As Modulators Of Gpcrs, Ricardo Rosas Jr.

Dissertations (1934 -)

G protein-coupled receptors (GPCRs) are cell surface receptors that transduce extracellular signals into intracellular effector pathways via heterotrimeric G protein dependent and independent pathways. GPCRs are involved in numerous physiological processes and are implicated in pathological signaling for numerous diseases. Described herein are novel approaches towards the modulation of two specific Class A GPCRs: protease activated receptor 1 (PAR1) and the mu opioid receptor (MOR). Chapter 1 provides a general introduction to GPCRs, which includes structures, signaling, and putative heteromer formation. Chapters 2 and 5 provide background information on PARs and the MOR, respectively. Diverse approaches towards the modulation of …


Resonant Two-Photon Ionization And Velocity Mapped Ion Imaging Studies Of Aromatic Van Der Waals Complexes, James T. Makuvaza Jul 2021

Resonant Two-Photon Ionization And Velocity Mapped Ion Imaging Studies Of Aromatic Van Der Waals Complexes, James T. Makuvaza

Dissertations (1934 -)

The study of van der Waals complexes provides a means for understanding the nature and strength of non-covalent interactions. Non-covalent interactions including C-H/, C-H/O, C-H/N, C-H/F, halogen and chalcogen bonding are found in important intermediates that regulate chemical and biological processes in many forefront areas of science including molecular self-assembly, drug substrate interactions, supramolecular chemistry, crystal engineering and biochemistry. To better understand these interactions, laser spectroscopic techniques that include mass selected two color resonant two photon ionization (2CR2PI) and velocity mapped ion imaging spectroscopy in combination with complementary ab initio calculations were used to probe the electronic structure, geometries, and …


Development Of Mqct Method For Calculations Of Collisional Energy Transfer For Astrochemistry And Planetary Atmospheres, Bikramaditya Mandal Apr 2021

Development Of Mqct Method For Calculations Of Collisional Energy Transfer For Astrochemistry And Planetary Atmospheres, Bikramaditya Mandal

Dissertations (1934 -)

A mixed quantum/classical methodology and an efficient computer code, named MQCT, were developed to model molecular energy transfer processes relevant to astrochemical environments and planetary atmospheres and applied to several real systems. In particular, the rotational energy transfer in N2 + Na collisions was studied with the focus on quantum phase, differential cross-sections, and scattering resonances, and excellent agreement with full quantum results was found. For H2O + H2, detailed calculations were carried out with the focus on allowed vs. forbidden transitions between the ortho/para states of both collision partners. Again, excellent agreement with full quantum calculations was achieved. Calculations …


Design And Synthesis Of Selective Estrogen Receptor Agonists, Edward Edward Wetzel Apr 2021

Design And Synthesis Of Selective Estrogen Receptor Agonists, Edward Edward Wetzel

Dissertations (1934 -)

Estrogens are hormones that regulates many different physiological functions. A decline in estrogen leads to significant issues that decrease the quality of life. Past treatments of menopausal symptoms included the administration of estrogen. However, side effects such as an increased risk of breast cancer, made this an unattractive therapeutic option. When a new estrogen receptor (ERβ) was discovered, it provided new hope for hormone replacement therapy (HRT). ERβ was shown to inhibit tumor growth, whereas ERα regulates breast cancer proliferation in certain types of breast cancer. The therapeutic benefits of targeting ERβ are vast; herein we focus on the benefits …


Toward Understanding The Origin Of Mass-Independent Fractionation In Sulfur Allotropes And In Ozone, Igor Gayday Apr 2021

Toward Understanding The Origin Of Mass-Independent Fractionation In Sulfur Allotropes And In Ozone, Igor Gayday

Dissertations (1934 -)

Mysterious isotope effects, found in atmospheric ozone, cannot be explained by the standard mass-dependent statistical model. Similar mass-dependent isotope effects were also uncovered in sulfur deposits older than 2 billion years. In an effort to pinpoint possible reasons of these isotope effects, we build a theoretical description of the recombination reactions in sulfur allotropes and in ozone. No potential energy surface exists for the sulfur allotropes, so electronic structure calculations are also required. Ab initio calculation of two dimensionally reduced (2D and 3D) models of the potential energy surface for the tetrasulfur molecule at CCSD(T)-F12 and MRCI levels of theory …


Synthetic And Mechanistic Studies Of Ruthenium Catalyzed C-C, C-H And C-N Bond Activation Reactions, Nuwan Asanka Pannilawithana Apr 2021

Synthetic And Mechanistic Studies Of Ruthenium Catalyzed C-C, C-H And C-N Bond Activation Reactions, Nuwan Asanka Pannilawithana

Dissertations (1934 -)

Transition metal-catalyzed selective CH, CC and CN bond activation reactions represent a challenging and synthetically important field in organic chemistry. In particular, transition-metal catalytic unreactive bond activation protocols are applicable in various stereoselective and atom economical complex organic molecule synthesis. Recently, significant research efforts have been made for utilizing catalytic CH and CC bond cleavage methods in the further development of commercially valuable pharmaceuticals and agrochemicals. The well-defined cationic Ru–H complex was found to be an effective catalyst for mediating the coupling reaction of 1,2-disubstituted indoles with α,β-unsaturated aldehydes and ketones, in which the regioselective Cα–Cβ activation of the carbonyl …


Scope And Mechanistic Studies Of Ruthenium Catalyzed C-N Bond Activation Reactions, Pandula Taepith Kirinde Arachchige Apr 2021

Scope And Mechanistic Studies Of Ruthenium Catalyzed C-N Bond Activation Reactions, Pandula Taepith Kirinde Arachchige

Dissertations (1934 -)

Primary aliphatic amines which are ubiquitous in natural products, traditionally considered as inert to substitution reactions. Recent studies clearly demonstrated that the aliphatic deaminative coupling chemistry can be used to make valuable scaffolds through C–N bond activation on transition metal complexes. The catalytic system generated in situ from the tetranuclear Ru–H complex with a catechol ligand (2-9/2-16) and independently synthesized ruthenium catecholate complex 2-11 was found to be effective for the direct deaminative coupling of primary amines. The catalytic system formed in-situ from the reaction of cationic Ru–H complex 2-10 with 3,4,5,6-tetrachloro-1,2-benzoquinone 2-12 was found to mediate a regioselective deaminative …


1. Dft-Guided Discovery Of Hybrid Catalysts For C-C Bond Formation; 2. Synthesis Of A Reported Pdi Inhibitor, Eric Greve Jul 2020

1. Dft-Guided Discovery Of Hybrid Catalysts For C-C Bond Formation; 2. Synthesis Of A Reported Pdi Inhibitor, Eric Greve

Dissertations (1934 -)

1. Dual amine/pi Lewis acid catalyst systems have been reported for intramolecular direct additions of aldehydes/ketones to unactivated alkynes and occasionally alkenes, but related intermolecular reactions are rare. We reasoned that bulky metal ligands and bulky amine catalysts could minimize catalyst poisoning and could facilitate certain examples of direct intermolecular additions of unactivated aldehydes/ketones to alkenes/alkynes. Density Functional Theory (DFT) ground state calculations on putative catalytic intermediates for alkyne versus organocatalyst complexation to the -acid, and also the key carbon-carbon bond formation were used to prioritize ligand/organocatalyst combinations. Our calculations suggested that PyBOX-Pt(II) catalysts for alkene/alkyne activation could be combined …


Hybrid Metal/Covalent Organic Frameworks For Solar Fuel Conversion, Sizhuo Yang Apr 2020

Hybrid Metal/Covalent Organic Frameworks For Solar Fuel Conversion, Sizhuo Yang

Dissertations (1934 -)

Due to the harsh environment issues such as air pollution and global warming and global energy crisis raised by using fossil fuels, it is urgent to find an alternative sustainable energy source. How to utilize solar energy-the most clean and abundant energy source on earth is challenging. Convert solar energy to clean fuel energy like H2 or hydrocarbons is ideal energy conversion strategy. Thus, design new materials for hydrogen generation or CO2 reduction have attract researcher’s attention.The present study focuses on two types of materials of interest, the first of which is Metal Organic Frameworks (MOFs), including enhancing the …


Theoretical And Experimental Investigation Of Non-Covalent Interactions In S-Nitrosothiols And Thio-Carboxylic Acids, Niloufar Hendinejad Apr 2020

Theoretical And Experimental Investigation Of Non-Covalent Interactions In S-Nitrosothiols And Thio-Carboxylic Acids, Niloufar Hendinejad

Dissertations (1934 -)

S-Nitrosothiols (RSNOs) are ubiquitous biomolecules whose chemistry is tightly controlled in unknown. In this work, we demonstrate, using high-level ab initio and DFT calculations, the ability of RSNOs to participate in intermolecular interactions with electron pair donors/Lewis bases (LBs) via a σ-hole, a region of positive electrostatic potential on the molecular surface at the extension of the N–S bond. Analysis of the nature of the intermolecular interactions in σ-hole bound RSNO-LB complexes shows the dominant role of electrostatic and dispersion interactions. Importantly, σ-hole binding is able to modulate the properties of RSNOs by changing the balance between two chemically opposite …


Hybrid Catalysis For The Direct Addition Of Unactivated Aldehydes And Ketones To Alkenes And Alkynes, Jacob Porter Oct 2019

Hybrid Catalysis For The Direct Addition Of Unactivated Aldehydes And Ketones To Alkenes And Alkynes, Jacob Porter

Dissertations (1934 -)

Reactions for the alpha functionalization of carbonyl compounds are important for the synthesis of complex organic materials such as pharmaceuticals, agrochemicals, and natural products. Current methodology used to perform these reactions is inefficient in that pre-activated coupling partners or sensitive catalysts are usually required. Described herein is the study and development of bifunctional and dual catalytic systems for carbon-carbon bond formation via the direct addition of unactivated carbonyl compounds to unactivated alkenes/alkynes. A dual catalyst system is one which utilizes two distinct catalysts to simultaneously activate separate reactants, and in a bifunctional catalyst the two catalytic components are present separately …


Structure And Mechanisms Of Metalloenzymes For Incorporation Of Water Across Cn And C-Cl Bonds, Xinhang Yang Jul 2019

Structure And Mechanisms Of Metalloenzymes For Incorporation Of Water Across Cn And C-Cl Bonds, Xinhang Yang

Dissertations (1934 -)

Metalloenzymes are widely involved in water incorporation across CN and C-Cl bonds.1 In this research, the structure and mechanisms of two novel metalloenzymes that incorporate water across CN and C-Cl bonds were examined by biophysical approaches, computational modeling, and crystallographic methods.In the research of water incorporation across CN bonds, a novel eukaryotic nitrile hydratase (NHase, EC 4.2.1.84) from Monosiga brevicollis (MbNHase) was characterized, and the functional role of a (His)17 section and an insert region in the MbNHase, were examined by gene modifications. Each of these MbNHase enzymes provided an 22 heterotetramer, identical to that observed for prokaryotic NHases …


Investigation Of The Active Site Maturation And Catalytic Mechanism Of Nitrile Hydratases (Nhase, E.C.4.2.1.84), Irene Anyango Ogutu Jul 2019

Investigation Of The Active Site Maturation And Catalytic Mechanism Of Nitrile Hydratases (Nhase, E.C.4.2.1.84), Irene Anyango Ogutu

Dissertations (1934 -)

Nitrile hydratase (NHase, E.C.4.2.1.84) is a metalloenzyme that catalyzes the hydration of nitriles into their corresponding amide under ambient conditions. NHase enzymes contain either a non-heme Fe3+ ion or a non-corrin Co3+ ion in their active site. NHase enzymes have industrial applications as biocatalysts in the large-scale production of acrylamide and nicotinamide, though it’s catalytic and biochemical properties are not fully understood. This research project provides insight into the active site maturation process and catalytic mechanism of NHase using peptide model complexes, site-directed mutagenesis and synthesis of deuterated proteins.Insight into the sequential maturation of the NHase active site has been …


The Alpha-Activator Complex, Cellular Maturation, And Catalytic Mechanism Of Iron-Type Nitrile Hydratase, Wasantha Lankathilaka Karunagala Pathiranage Jul 2019

The Alpha-Activator Complex, Cellular Maturation, And Catalytic Mechanism Of Iron-Type Nitrile Hydratase, Wasantha Lankathilaka Karunagala Pathiranage

Dissertations (1934 -)

In industry, chemicals are typically synthesized through catalytically accelerated chemical processes. The use of biocatalysts is an increasingly important trend in achieving environmentally friendly chemical production processes. Nitrile Hydratases (NHases) are well-known biocatalysts that are used by several manufacturers such as Mitsubishi Rayon Corporation and Lonza for the conversion of acrylonitrile to acrylamide and 3-cyanopyridine to nicotinamide, respectively. Amides, in general, are used in polymer preparation, adhesive manufacturing, and the paper industry. Refrigeration is needed in the enzymatic hydration process on the industrial scale to maintain a low reaction temperature to stabilize the NHase enzyme. The use of whole cells …


Design And Synthesis Of Simplified Analogs Of The Natural Product Sordarin As Potential Antifungal Agents, Yibiao Wu Apr 2019

Design And Synthesis Of Simplified Analogs Of The Natural Product Sordarin As Potential Antifungal Agents, Yibiao Wu

Dissertations (1934 -)

Invasive fungal infection is a life-threatening illness that causes high mortality, and is especially common among patients with compromised immune systems. However, currently there are only three major classes of clinically useful drugs capable of treating such infections. In addition, due to the fact that drug resistance has become a serious issue especially among patients who suffer from chronic infections, it is urgent to identify new drug candidates, particular those of new classes. The discovery of the natural product sordarin and its novel mechanism of action of inhibiting fungal protein synthesis via the fungal eukaryotic elongation factor 2 (eEF2) led …


Photochemical Expulsion Of Leaving Groups From A Naphthothiophene-2-Carboxamide Linked To A Chromophore, Lingzi Li Jul 2018

Photochemical Expulsion Of Leaving Groups From A Naphthothiophene-2-Carboxamide Linked To A Chromophore, Lingzi Li

Dissertations (1934 -)

Two bichromophoric systems were synthesized which have thioxanthone as the chromophore that absorbs the incident light and a naphthothiophene-2-carboxanilide, which serves as a triplet excited state energy acceptor. Upon excitation the triplet excited state of the thioxanthone is populated via intersystem crossing, which is efficient with isc = 0.68. Based on the relative energies of the triplet excited states of thioxanthone (ET = 65 kcal mol-1) and naphthothiophene (ET = 51 kcal mol-1), the subsequent triplet excited state energy transfer to generate the triplet excited state of the naphthothiophene-2-carboxamide should be a very rapid process that is 14 kcal mol1 …


Design, Synthesis And Study Of Redox And Optoelectronic Properties Of Aromatic Oxidants And Polycyclic Aromatic Hydrocarbons, Mohammad Mosharraf Hossain Jul 2018

Design, Synthesis And Study Of Redox And Optoelectronic Properties Of Aromatic Oxidants And Polycyclic Aromatic Hydrocarbons, Mohammad Mosharraf Hossain

Dissertations (1934 -)

Organic materials play a significant role for the next generation photovoltaic devices that convert solar energy into usable forms of energy. In this regard, polycyclic aromatic hydrocarbons (PAHs) are fundamental tools in the developing area of molecular electronics and photovoltaics as they show excellent optical/electronic properties and are well-suited for applications in such developing areas as flexible display devices, field effect transistors and solar cell panels. Design and synthesis of novel materials for photovoltaics applications would require the proper understanding the mechanism of charge transport and identification of the structural features necessary in a particular molecular wire or PAH. To …


The Photodynamic And Structural Analyses Of Advanced Materials For Solar Fuel Conversion, Brian Pattengale Jul 2018

The Photodynamic And Structural Analyses Of Advanced Materials For Solar Fuel Conversion, Brian Pattengale

Dissertations (1934 -)

Mitigating the current and future climate and pollution issues that have been brought on by the combustion of fossil fuels is of utmost importance and will rely on, in part, the availability of renewable fuel sources. Of the possible sources of energy, solar is abundant, but must be harnessed efficiently and stored as a solar fuel to overcome the current storage issues that limit photovoltaic cells. One such fuel, H2(g), represents a carbon-neutral source of energy if it can be efficiently liberated from water via the water splitting reaction. Thus, much attention is focused on designing materials to perform the …


Photoremovable Protecting Groups Based On Electrocyclization With Leaving Group Expulsion Via A Proposed Zwitterion, Gilbert Ndzeidze Apr 2018

Photoremovable Protecting Groups Based On Electrocyclization With Leaving Group Expulsion Via A Proposed Zwitterion, Gilbert Ndzeidze

Dissertations (1934 -)

The triplet excited state of thioxanthone produced by photolysis undergoes reversible triplet energy transfer with a trimethylene - linked benzothiophene-2-carboxanilide ring system. The ensuing electrocyclic ring closure of the anilide moiety produces a putative zwitterionic intermediate that is capable of expelling leaving groups (LG-) from the C-3 position of the benzothiophene ring. Stern-Volmer quenching studies with cyclohexadiene as quencher furnish the rate constants for the triplet excitation transfer in the forward and reverse directions, which can be expressed as an equilibrium constant K = 0.058. Overall, the rate of triplet excited state reaction becomes K x kr = 5.7 x …


Synthesis And Characterization Of Biomimetic Models Of Mononuclear Nonheme Iron Dioxygenases And Their Reactive Intermediates, Anne Alyse Fischer Apr 2018

Synthesis And Characterization Of Biomimetic Models Of Mononuclear Nonheme Iron Dioxygenases And Their Reactive Intermediates, Anne Alyse Fischer

Dissertations (1934 -)

Mononuclear non-heme iron dioxygenases (MNIDs) are a class of enzymes that catalyze a variety of reactions, from amino acid catabolism to bioremediation using molecular oxygen. This work focuses on three types of MNIDs: thiol dioxygenaes (TDOs), aminophenoldioxygenases (APDOs), and sulfoxide synthases (SOSs). TDOs, found in mammals, regulate the levels of cysteine along with other thiol-containing molecules, using molecular oxygen to convert them into their corresponding sulfinic acids. APDOs catalyze the oxidative ring cleavage in the biodegradation of nitroaromatics. SOSs are involved in the biosynthesis of large biologically relevant molecules in humans. Although this class of enzymes has gained more attention …


Nucleotide-Dependent Preferential Localization Of Ras In Model Membranes With Lipid Raft Nanodomains, Anna Shishina Oct 2017

Nucleotide-Dependent Preferential Localization Of Ras In Model Membranes With Lipid Raft Nanodomains, Anna Shishina

Dissertations (1934 -)

Membrane proteins constitute a third of all proteins in the cell and more than 50% of drug targets. However, the analysis of membrane proteins has many challenges owing to their partially hydrophobic surfaces, flexibility and lack of stability. One example of an essential membrane protein is Ras superfamily. Ras is a small monomeric GTPase involved in regulation of cell growth, proliferation and differentiation. Therefore, Ras and its effectors are among the most important targets for cancer therapy. A detailed knowledge of the processes occurring during signal propagation via Ras might help to elucidate the mechanisms of the involved signal cascades. …


Spectral Characterization Of Cytochromes P450 Active Sites Using Nmr And Resonance Raman Spectroscopy, Remigio Usai Oct 2017

Spectral Characterization Of Cytochromes P450 Active Sites Using Nmr And Resonance Raman Spectroscopy, Remigio Usai

Dissertations (1934 -)

The Cytochrome P450 (P450s) has been the subject of intense research for over six decades. An efficient approach for isotopic labeling of the prosthetic group in heme proteins was exploited to produce an analogue of the soluble bacterial cytochrome P450cam (P450cam) that contains a 13C labeled-protoheme prosthetic group. HU227 strain of E. coli, which lacks the δ-aminolevulinic acid (δ-ALA) synthase gene, was employed in the heterologous expression of P450cam harboring a prosthetic group labeled with 13C at the Cm and Cα positions by growing cells in the presence of [5-13C] δ-ALA, which was synthesized in four steps from [2-13C] glycine. …


Mixed Quantum/Classical Theory (Mqct) For Rotationally And Vibrationally Inelastic Scattering And Its Application To The Molecules Of Astrochemical Importance, Alexander Semenov Jul 2017

Mixed Quantum/Classical Theory (Mqct) For Rotationally And Vibrationally Inelastic Scattering And Its Application To The Molecules Of Astrochemical Importance, Alexander Semenov

Dissertations (1934 -)

This thesis presents developments and applications of the mixed quantum/classical theory (MQCT) for inelastic scattering. In this approach, translational motion of collision partners is treated classically, while the internal degrees of freedom – rotational and/or vibrational motion – are treated quantum mechanically. Within this framework calculations of rotationally inelastic cross sections are carried out in a broad range of collision energies and results are compared against the exact full quantum data for several real systems. For CO +He, N2 + Na and H2 + He the agreement is excellent through six orders of magnitude range of cross sections values and …