Viral RNA dependent RNA polymerases (RdRps) are enzymes which enable RNA viruses to replicate their genome and to prepare mRNA for translation of viral proteins. Due to its relative evolutionary conservation RdRps are good targets for drug design. In this work we present a structure of the RdRp (3Dpol ) of Aichi virus, which has not been solved yet. Aichi virus is a human pathogen that causes gastroenteritis. Aichi virus is also used as a model organism for studying cognate viruses which virulence is more dangerous, for example: Rhinovirus, Hepatitis A virus, SARS virus, hepatitis C virus, yellow fever, and West-Nile virus. In addition to structural studies of Aichi virus 3Dpol we also tested a previously published hypothesis that, 3Dpol is recruited to the membrane through phosphatidylinositol 4 phosphate (PI4P) - an important regulatory lipid. Membranes highly enriched in PI4P are formed in cells infected by single stranded positive sense RNA (plus ssRNA) viruses. Finally we tested the influence of ribonucleotides on the 3Dpol protein stability. (In Czech)

Thesis (M.Sc.)--University of the Witwatersrand, Faculty of Science, School of Molecular and Cell Biology, 2018. / ABSTRACT The Retinoblastoma binding protein 6 is dysregulated in most cancers, indicating it may play a role in metabolic reprograming- a hallmark of carcinogenesis. Its human isoforms have been shown to play diverse roles in apoptosis. This study aimed to elucidate biochemical roles of RBBP6 isoforms in metabolic reprogramming during carcinogenesis. Drosophila melanogaster wild type and p53 null mutants were treated with drug permutations of irinotecan (DNA damaging agent) and exogenous pyruvate to perturb metabolism. Moreover, using RT-PCR and Western blot expression profiles of SNAMA (Drosophila Orthologue of RBBP6) isoforms were shown followed by survival studies to investigate the effects of these drugs. Furthermore, using bioinformatics the domains of RBBP6 isoforms in various species were shown. Results indicate that RBBP6 isoforms show contrasting expression patterns. Furthermore, exogenous pyruvate protects the wild type flies from irinotecan toxicity while killing p53 null mutants. RBBP6 proves to be a potential druggable target for chemotherapy. / EM2018

Proteins and fatty acids often exist in solutions containing biological matter that are treated with membranes. These proteins and fatty acids interact with each other as well as with the membranes thereby affecting the flux. Binding of fatty acids to proteins results in complexes that are much larger than fatty acid molecules. Exploitation of this size difference to remove difficult to separate fatty acids from aqueous solutions by ultrafiltration was investigated in this study. In addition, the fouling of membrane by the protein-fatty acid mixtures containing free dissolved fatty acids was studied using bovine albumin (BSA)-caprylic system. Binding of caprylic acid to native and pasteurized BSA was examined by diafiltering pre equilibrated fatty acid-BSA mixtures. The rate of mass transfer of fatty acid molecules through boundary film surrounding the protein molecules was estimated using a BSA solution as the adsorbent phase in an agitated column. A stirred cell fitted with a polyethersulfone membrane (30 kDa) was used for the diafiltrations. Accumulation of fatty acid in the BSA layers fouled on the membrane was also estimated. Binding studies indicate that a native BSA molecule (at pH 6.8) could bind 7 fatty acid molecules in specific binding cavities while approximately 44 molecules are bound onto the surface. When BSA was pasteurized the specific binding decreased from 7 to 2 indicating unfolding of the molecule. In addition, the total binding capacity decreased from 44 to 24 moles/BSA mole and the rate of mass transfer decreased from 4.5/min to 3.6/min, indicating heat induced aggregation of BSA. At alkaline pH levels fatty acid anion acts as an anionic surfactant stabilizing the molecular conformation of the protein and reducing fouling. When pH was lowered to 3, flux severely declined. Unusually large accumulation of fatty acid in the deposited protein layers (caprylic/BSA ~ 10,000 moles) occurred indicating capillary condensation of undissociated fatty acids in the protein layer. Agitated column studies showed that proteins could be used as an adsorbent to remove hard to separate dissolved fatty acids from aqueous solutions. The separated protein-fatty acid complex may be further processed to manufacture animal feed.

Thesis (Ph. D.)--University of Chicago, Dept. of Chemistry, December 2003. / Includes bibliographical references. Also available on the Internet.

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Thesis (Ph.D.)--Murdoch University, 2006. / Thesis submitted to the Division of Science and Engineering. Bibliography: leaves 257-284.