Life Sciences Commons^™

The Role Of Liver Sinusoidal Endothelial Cells In Liver Malady Homeostasis, Fatima Cabral

Department of Biochemistry: Dissertations, Theses, and Student Research

Current literature described techniques for the purification of liver cell types through text alone. The techniques described for the isolation of liver sinusoidal endothelial cells as well as hepatocytes described here are modified from a published article in the Journal of Visualized experiments. The video protocol allows for the user to successfully isolate cells as the most difficult parts of the procedure are demonstrated visually. The detection of liver maladies such as the non-alcoholic fatty liver disease, the stage if this disease and differentiation between non-alcoholic and alcoholic fatty liver disease is demonstrated in the development of a unique panel …

Dissecting The Regulatory Network Of Sphingolipid Biosynthesis In Plants, Ariadna Gonzalez-Solis

Department of Biochemistry: Dissertations, Theses, and Student Research

Sphingolipids are a diverse group of lipids recognized as important components of cellular membranes and regulators of processes during development and in response to environmental stresses. Serine palmitoyltransferase (SPT) catalyzes the first step in sphingolipid biosynthesis and is a primary regulatory point for homeostasis. ORM proteins have been identified as negative regulators of SPT activity, however the mechanistic details of the regulation are only beginning to be understood. In this work, we show that ORM1 and ORM2 are essential for life cycle completion in Arabidopsis thaliana. Furthermore, the study of a structural ORM1 variant provided information about a transmembrane …

Characterization Of Human Pyrroline-5-Carboxylate Reductase Enzymes Responsible For L-Proline Biosynthesis, Sagar Patel

Department of Biochemistry: Dissertations, Theses, and Student Research

Pyrroline-5-carboxylate reductases (EC 1.5.1.2) are important housekeeping enzymes of L-proline biosynthesis, which generate L-proline and influence redox cycling of NAD(P)H/NAD(P)⁺ to support cellular growth in all domains of life. Structural evidence from X-ray crystal structures of HsPYCR1 (PDB codes 5UAT, 5UAU, and 5UAV) shows both NADPH bound in the N-terminal Rao-Rossmann fold motif and an important hydrogen bond or proton donor role for Thr238 with L-P5C. The Thr238Ala mutation results in 10-fold loss in catalytic efficiency with varied L-P5C relative to the wild-type enzyme, thus indicating Thr238’s potential hydrogen bond and proton donation to L-P5C is critical for catalysis. …

Protease Oma1 Modulates Mitochondrial Bioenergetics And Ultrastructure Through Dynamic Association With Micos Complex, Martonio P. Viana

Department of Biochemistry: Dissertations, Theses, and Student Research

Remodeling of mitochondrial ultrastructure is a complex dynamic process that is critical for a variety of mitochondrial functions and apoptosis. Although the key regulators of this process - mitochondrial contact site and cristae junction organizing system (MICOS) and GTPase Optic Atrophy 1 (OPA1) have been characterized, the mechanisms behind this regulation remain incompletely defined. Here, we found that in addition to its role in mitochondrial division, metallopeptidase OMA1 is required for maintenance of contacts between the inner and outer membranes through a dynamic association with MICOS. This association is independent of OPA1, appears to be mediated via the MIC60 MICOS …

The Role Of Conformational Dynamics In Isocyanide Hydratase Catalysis, Medhanjali Dasgupta

Department of Biochemistry: Dissertations, Theses, and Student Research

Post-translational modification of cysteine residues can regulate protein function and is essential for catalysis by cysteine-dependent enzymes. Covalent modifications neutralize charge on the reactive cysteine thiolate anion and thus alter the active site electrostatic environment. Although a vast number of enzymes rely on cysteine modification for function, precisely how altered structural and electrostatic states of cysteine affect protein dynamics, which in turn, affects catalysis, remains poorly understood.

Here we use X-ray crystallography, computer simulations, site directed mutagenesis and enzyme kinetics to characterize how covalent modification of the active site cysteine residue in the enzyme, isocyanide hydratase (ICH), affects the protein …