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Articles 121 - 125 of 125

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

Structural Investigation Of Atp-Utilizing Enzymes: Structures Involved In H+ Homeostasis And The Proliferation Of Hormone-Dependent Cancers, Zacariah Louis Hildenbrand Jan 2010

Structural Investigation Of Atp-Utilizing Enzymes: Structures Involved In H+ Homeostasis And The Proliferation Of Hormone-Dependent Cancers, Zacariah Louis Hildenbrand

Open Access Theses & Dissertations

ATP is a multifunctional nucleotide considered to be the "molecular unit of currency" of intracellular energy transfer. ATP is utilized ubiquitously for the transport of chemical energy within the cell in addition to acting as a substrate in the regulation of many metabolic and signaling transduction pathways such as kinase-mediated signaling cascades. Interestingly, the functional mechanisms of many enzymes require the binding of ATP to trigger key structural and conformational changes that ultimately result in enzyme-directed catalysis. Two of the most omnipresent ATPases within the cell include the V-ATPase rotary proton pump and the Hsp90 protein-folding chaperone. Structural and biochemical …


Lipid Uptake And Metabolism In The Parasitic Protozoan Giardia Lamblia., Mayte Yichoy Jan 2009

Lipid Uptake And Metabolism In The Parasitic Protozoan Giardia Lamblia., Mayte Yichoy

Open Access Theses & Dissertations

Giardia lamblia is a protozoan parasite that causes various intestinal syndromes, and it is a common cause of water-borne illness worldwide, both in developed and developing countries. Giardia attaches to the mucosal epithelia of the duodenum below the bile duct, where it is exposed to bile salts and dietary lipids. G. lamblia is unable to synthesize lipids de novo and must therefore scavenge necessary lipids from its extracellular environment and remodel them as needed. However, the current lipidomic analysis (presented in this Dissertation) has revealed that while the Giardia lipidome is rich in phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylglycerol (PG), …


Molecular Characterization Of Trypanosoma Cruzi And Shed Vesicle Components Involved In Host Immunomodulation And Cell Invasion, Ernesto Satoshi Nakayasu Jan 2008

Molecular Characterization Of Trypanosoma Cruzi And Shed Vesicle Components Involved In Host Immunomodulation And Cell Invasion, Ernesto Satoshi Nakayasu

Open Access Theses & Dissertations

Chagas disease caused by Trypanosoma cruzi is a devastating infectious disease with millions of cases in Latin America, and recently became a public health concern in United States and Europe. Although many efforts have been made for the development of an effective immunotherapy, currently there is no human vaccine for Chagas disease. Thus, the treatment is based only on two drugs that have limited efficacy and in some cases present severe side effects. One restriction for the rational approach to develop new therapies against this disease is the limited information about the proteins, glycolipids and protein posttranslational modifications expressed by …


The Role Of Protein Disulfide Isomerase (Pdi) In Oxidative Folding, Veronica Gonzalez Jan 2008

The Role Of Protein Disulfide Isomerase (Pdi) In Oxidative Folding, Veronica Gonzalez

Open Access Theses & Dissertations

Protein Disulfide Isomerase is a highly evolved oxidoreductase enzyme that has the capability of oxidizing, reducing, and isomerizing disulfides in substrate. PDI is organized into several domains denoted a, b, b', a' and c. These domains are believed to have different functions but all must be present for full PDI activity. In this manuscript we recorded the ability of PDI b' to catalyze oxidative folding in fully reduced RNase A. We also examined competition between thiol-disulfide shuffling and conformational folding by PDI. This competition creates a rough effect of a highly efficient enzyme in two different substrates: RNase A and …


Giardia Lamblia: Genomic And Molecular Analyses Of Flippase, Diana Leticia Villazana-Kretzer Jan 2008

Giardia Lamblia: Genomic And Molecular Analyses Of Flippase, Diana Leticia Villazana-Kretzer

Open Access Theses & Dissertations

Giardia lamblia, is an intestinal protozoan parasite responsible as a major cause of water-borne intestinal infection in humans (giardiasis). It has been proposed earlier that Giardia has limited lipid synThesis ability and therefore relies on preformed lipid molecules from outside sources. It has also been proposed that lipids are taken up through passive and active transport, and giardial flippasse play a significant role in this process. This study describes the identification and characterization of a putative homologue of flippase gene from Giardia. Flippase is an enzyme that functions as a trans-bilayer transport system facilitating the flip flop diffusion of phospholipids …