Lipids Commons^™

Nanodiscs: A Novel Approach To The Study Of The Methionine Abc Transporter System, Michael T. Winslow

Master's Theses

Membrane transporter proteins play the vital role of moving compounds in and out of the cell and are essential for all living organisms. ATP Binding Cassette (ABC) family transporters function both as importers and exporters in prokaryotes. MetNI is an E. coli Type I ABC transporter responsible for the uptake of methionine into the cytosol from the cell periplasmic space through the cell membrane to maintain intracellular methionine pools. ABC transporters, like other membrane proteins, are most often mechanistically and structurally studied in vitro, solubilized by detergents. However, detergent micelles may affect the conformational changes of membrane proteins relative to …

Flippase Inhibitors As Antimicrobial Agents, Robert Tancer

Seton Hall University Dissertations and Theses (ETDs)

Drug resistant microbes are a considerable challenge for modern medicine to overcome. The research described in this dissertation involved development of lipid flippase inhibitors and investigating their potential as antimicrobial agents against various drug resistant microbes. The microbes primarily investigated were methicillin resistant Staphylococcus aureus (MRSA) & Cryptococcus neoformans. Chapter 1 reviews the historical perspective and summarizes the current state of the field of research. In Chapter 2, the design space of an antimicrobial peptide known as humimycin was explored and the effects of modifications on its structure were observed against MRSA. Several key observations resulted. Most notably, the …

Molecular Dynamics Simulations Of Self-Assemblies In Nature And Nanotechnology, Phu Khanh Tang

Dissertations, Theses, and Capstone Projects

Nature usually divides complex systems into smaller building blocks specializing in a few tasks since one entity cannot achieve everything. Therefore, self-assembly is a robust tool exploited by Nature to build hierarchical systems that accomplish unique functions. The cell membrane distinguishes itself as an example of Nature’s self-assembly, defining and protecting the cell. By mimicking Nature’s designs using synthetically designed self-assemblies, researchers with advanced nanotechnological comprehension can manipulate these synthetic self-assemblies to improve many aspects of modern medicine and materials science. Understanding the competing underlying molecular interactions in self-assembly is always of interest to the academic scientific community and industry. …

The Structural And Functional Role Of Photosensing In Rgs-Lov Proteins, Zaynab Jaber

Dissertations, Theses, and Capstone Projects

Light provides organisms with energy and spatiotemporal information. To survive and adapt, organisms have developed the ability to sense light to drive biochemical effects that underlie vision, entrainment of circadian rhythm, stress response, virulence, and many other important molecularly driven responses. Blue-light sensing Light-Oxygen-Voltage (LOV) domains are ubiquitous across multiple kingdoms of life and modulate various physiological events via diverse effector domains. Using a small molecule flavin chromophore, the LOV domain undergoes light-dependent structural changes leading to activation or repression of these catalytic and non-catalytic effectors. In silico analyses of high-throughput genomic sequencing data has led to the marked expansion …

Complexation Of Glycoalkaloid Α- Tomatine With Sterols And Its Potential Application As An Anti-Cancer Drug, Bishal Nepal

Dissertations

Glycoalkaloids (GAs) are secondary metabolites found mostly in higher plant species and some marine invertebrates. They are known to form complexes with 3β-hydroxy sterols such as cholesterol causing membrane disruption. So far the visual evidence showcasing the complexes formed between glycoalkaloids and sterols has been mainly restricted to some earlier studies using Brewster angle microscopy. This study aimed to develop a method for topographic and morphological analysis of sterol-glycoalkaloid complexes. Langmuir-Blodgett (LB) transfer of monolayers comprising of glycoalkaloid tomatine, sterols, and lipids in varying molar ratios onto mica followed by AFM examination was performed. The AFM method used required minimal …

Finding The Balance​ The Effects Of Α-Cyclodextrin, 2-Hydroxypropyl-Β-Cyclodextrin, And Cholesterol Bacteroides Vulgatus And Clostridium Bolteae​, Bethany Weaver

Pence-Boyce STEM Student Scholarship

Atherosclerosis is a cardiovascular disease that is characterized by the hardening of arteries through the formation of cholesterol plaques. Cyclodextrins could potentially treat atherosclerosis by shrinking plaques. These cyclic oligosaccharides can make complexes with cholesterol but have also shown toxic side effects. This study looked for potential negative effects of cyclodextrins and cholesterol on gut bacteria. It was hypothesized that Bacteroides vulgatus will have decreased growth when grown in broth with cholesterol. In contrast, Clostridium bolteae will have decreased growth when grown in broth with cyclodextrins. Due to the fact that these bacteria are anaerobic, Clostridium bolteae and Bacteroides vulgatus …

Influence Of Single And Multiple Histidine Residues And Their Ionization Properties On Transmembrane Helix Dynamics, Orientations And Fraying, Fahmida Afrose

Graduate Theses and Dissertations

Since aromatic and charged residues are often present in various locations of transmembrane helices of integral membrane proteins, their impacts on the molecular properties of transmembrane proteins and their interactions with lipids are of particular interest in many studies. In this work, I used solid-state deuterium NMR spectroscopy in designed model peptide GWALP23 [GGALW(LA)6LWLAGA] with selective deuterium labels to addresses the pH dependence and influence of single and multiple “guest” histidine residues in the orientation and dynamic behaviors of transmembrane proteins. The mutations include Gly to His (G2/22 to H2/22), Trp to His (W5/19 to H5/19) and Leu to His …

Arachidin 3 Modulation Of Lipid Metabolism In Rotavirus Infections, Stormey Wisdom

Electronic Theses and Dissertations

Rotavirus (RV) can cause severe and deadly gastroenteritis in young children, infants, and immunocompromised individuals. Previous studies have shown that arachidin 3 (A3) inhibits RV replication, and that RV replication is dependent on the presence of lipids. This study investigated the alteration of lipid metabolism by A3 in RV infected HT29.f8 cells. A decrease in the RV regulation of lipid biosynthesis genes was observed with the addition of A3 using qRT-PCR. Also, immunofluorescent and histochemical staining for neutral fats, a major component of cellular lipid droplets, revealed an increased accumulation with both RV and RV+A3 when compared to no virus …

Chemical Tools To Characterize Membrane-Protein Binding Interactions Using Synthetic Lipid Probes, Meng Meng Rowland

Doctoral Dissertations

Signaling lipids such as diacylglycerol (DAG) and the phosphatidylinositol polyphosphates (PIP_ns) play crucial roles in numerous cellular pathways. However, characterization of their activities is hindered by the complexity of associated signaling pathways and of the membrane environment. To address this issue, we have developed lipid probes that are effective for characterizing biological events using different applications, including activity-based probing (PIP_ns and DAG) and microarray analysis (PIP_ns). The activity-based probes have been applied to label receptor targets in multiple cancer cell proteomes through photocrosslinking followed by click reactions. The probes were found to label several …

A Method For The Comparison Of Hdl Containing Apoprotein E And Hdl Cholesterol, Steven A. Knizner

Chemistry & Biochemistry Theses & Dissertations

Human serum high density lipoproteins (HDL) were isolated by preparative salt density gradient ultracentrifugation and analyzed further by heparin-sepharose affinity chromatography. Separation of the major classes of serum lipoproteins was achieved after a single ultracentrifugation on a salt density gradient at 272,000 x g for 36 hours in a swinging bucket rotor. After isolation, the total HDL was subdivided into HDL containing apoprotein E and HDL without this apoprotein by heparin-sepharose affinity chromatography. Relative amounts of these subclasses were then calculated.

HDL-cholesterol was measured after precipitation of LDL and VLDL by phosphotungstic acid and magnesium. The statistical relationship between HDL …

Development Of A Procedure For Analysis Of High Density Lipoprotein Subclasses, Chan Chin

Chemistry & Biochemistry Theses & Dissertations

Human serum high density lipoprotein subclasses, HDL₂ and HDL₃ , were isolated by preparative salt density gradient ultracentrifugation and further analyzed by electrophoresis on a 4 to 15% concentration gradient polyacrylamide gel.

The separation of the major classes of serum lipoproteins was achieved after a single ultracentrifugation for 272,000 g at 15°c in a swinging bucket rotor. High resolution concentration gradient gel electrophoresis was found to be particularly suitable for the separation of lipoproteins. The isolation of HDL by precipitation methods, heparin-manganese and dextran-magnesium have also been evaluated in this study, and were found not to completely separate …

Sulfatides As Opiate Receptors: An Evaluation Of The Opiate Binding Potential Of Sulfogalactosylgylcerolipid, Darby Geoghegan Hand

Chemistry & Biochemistry Theses & Dissertations

Cerebroside sulfate (CS) has recently been shown to bind opiate drugs in a pharmacologically relevent manner and therefore satisfy the structural requirements of an opiate receptor. Seminolipid (SGG), a novel sulfated galactosyl. glycerolipid that has been isolated from the testes of a variety of mammals, may be viewed as a structural analog of CS. In view of this structural similarity, it is reasonable to presume that SGG may also bind opiate drugs. The isolation of SGG from boar testes was accomplished using silica gel dry column chromotography with a chloroform: methanol water solvent system. The structure and purity of the …