Biochemistry, Biophysics, and Structural Biology Commons^™

Characterizing The Promiscuity Of Ligab, A Lignin Catabolite Degrading Extradiol Dioxygenase From Sphingomonas Paucimobilis Syk-6, Kevin P. Barry, Erika A. Taylor

Erika A. Taylor, Ph.D.

LigAB from Sphingomonas paucimobilis SYK-6 is the only structurally characterized dioxygenase of the largely uncharacterized superfamily of Type II extradiol dioxygenases (EDO). This enzyme catalyzes the oxidative ring-opening of protocatechuate (3,4-dihydroxybenzoic acid or PCA) in a pathway allowing the degradation of lignin derived aromatic compounds (LDACs). LigAB has also been shown to utilize two other LDACs from the same metabolic pathway as substrates, gallate, and 3-O-methyl gallate; however, kcat/KM had not been reported for any of these compounds. In order to assess the catalytic efficiency and get insights into the observed promiscuity of this enzyme, steady-state kinetic analyses were performed …

Comparative Metabolism Of Phenanthro[3,4-B]Thiophene And Benzo[C]Phenanthrene, Jaquan M. Williams

Jaquan M Williams

ABSTRACT OF THESIS Comparative Metabolism of Phenanthro[3,4-b]Thiophene And Benzo[c]Phenanthrene Polycyclic aromatic hydrocarbons (PAHs) and their sulfur-heterocyclic analogs (thia-PAHs) are commonly occurring persistent environmental contaminants formed by incomplete combustion of organic matter. A number of thia-PAHs have shown significant mutagenic and carcinogenic activities. As noted with PAHs, these chemical contaminants also require metabolic activation in order to exhibit their mutagenic and carcinogenic effects. In the present study, a comparison of the metabolism of highly mutagenic phenanthro[3,4-b]thiophene (P[3,4-b]T) and its weakly mutagenic carbon analogue, benzo[c]phenanthrene (B[c]P), was investigated. Metabolism studies were conducted using liver microsomes from induced rats, un-induced rats, as well …

Escherichia Coli Heptosyltransferase I: Investigation Of Protein Dynamics Of A Gt-B Structural Enzyme, Erika A. Taylor, Daniel J. Czyzyk, Shreya S. Sawant, Carlos A. Ramirez-Mondragon

Erika A. Taylor, Ph.D.

Heptosyltransferase I (HepI), the enzyme responsible for the transfer of l-glycero-d-manno-heptose to a 3-deoxy-α-d-manno-oct-2-ulopyranosonic acid (Kdo) of the growing core region of lipopolysaccharide, is a member of the GT-B structural class of enzymes. Crystal structures have revealed open and closed conformations of apo and ligand-bound GT-B enzymes, implying that large-scale protein conformational dynamics play a role in their reaction mechanism. Here we report transient kinetic analysis of conformational changes in HepI reported by intrinsic tryptophan fluorescence and present the first real-time evidence of a GT-B enzyme undergoing a substrate binding-induced transition from an open to closed state prior to catalysis.

Dna Damage Repair Genes Controlling Human Papillomavirus (Hpv) Episome Levels Under Conditions Of Stability And Extreme Instability, Terri G. Edwards, Thomas J. Vidmar, Kevin Koeller, James K. Bashkin, Chris Fisher

James Bashkin

Psychosine, The Cytotoxic Sphingolipid That Accumulates In Globoid Cell Leukodystrophy, Alters Membrane Architecture, Jacqueline A. Hawkins-Salsbury, Archana R. Parameswar, Xuntian Jiang, Paul H. Schlesinger, Ernesto Bongarzone, Daniel S. Ory, Alexei V. Demchenko, Mark S. Sands

Alexei Demchenko

Inhibition Of Bacillus Cereus Growth By Bacteriocin Producing Bacillus Subtilis Isolated From Fermented Baobab Seeds (Maari) Is Substrate Dependent, Donatien Kaboré, Dennis S. Nielsen, Hagrétoui Sawadogo-Lingan, Bréhima Diawara, Mamoudou H. Dicko Prof., Mogens Jakobsen, Line Thorsen

Pr. Mamoudou H. DICKO, PhD