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dc.contributor.advisorSanders, Daviden_US
dc.creatorKarunan Partha, Sarathyen_US
dc.date.accessioned2011-01-12T11:16:24Zen_US
dc.date.accessioned2013-01-04T04:23:49Z
dc.date.available2012-03-30T08:00:00Zen_US
dc.date.available2013-01-04T04:23:49Z
dc.date.created2010-10en_US
dc.date.issued2010-10en_US
dc.date.submittedOctober 2010en_US
dc.identifier.urihttp://hdl.handle.net/10388/etd-01122011-111624en_US
dc.description.abstractUDP-galactopyranose mutase (UGM) is a flavoenzyme which catalyzes the interconversion of UDP-galactopyranose (UDP-Galp) and UDP-galactofuranose (UDPGalf). UDP-Galf is the active precursor of Galf residues. Glycoconjugates of Galf residues are found in the cell wall of bacteria and on the cell surface of higher eukaryotes. Galf residues have not been found in humans and the fact that they are essential for the growth of pathogenic bacteria makes UGM a potential antibacterial target. In the present study, crystal structures of UGM from Deinocococcus radiodurans (drUGM) in complex with substrate (UDP-Galp) were determined. UDP-Galp is buried in the active site and bound in a U-shaped conformation. The binding mode and active site interactions of UDP-Galp are consistent with the previous biochemical and mechanistic studies. The mobile loops in the substrate complex structures exist in a closed conformation and Arg198 on one of the mobile loops stabilizes the phosphate groups of the substrate. The anomeric carbon of galactose is 2.8 Å from the N5 of FAD (in the reduced complex) favorable to form FAD-galactosyl adduct. In addition to substrate complex structures, the crystal structures of drUGM in complex with UDP, UMP, and UDP-Glc have been determined. The mobile loops in all these complexes exist in a closed conformation. Inhibitors for UGM were identified by ligand-based and structure-based methods. The phosphonate analog of UDP-Galp (GCP) showed only weak inhibition against various bacterial UGMs. The structure of drUGM in complex with GCP provided a basis for its inhibitory activity. Poor stabilization of the phosphate groups by conserved arginines (Arg198 and Arg305) and altered sugar binding mode account for its activity. Novel indole-based (LQ1, LQ6 and LQ10) inhibitors of UGM were identified through structure-based virtual screening (SBVS) of a chemical library. Inhibition studies also allowed the identification of an active site aspartic acid that plays role in inhibitor binding. The structural studies on drUGM provided a basis for understanding substrate binding to UGM. In vitro enzyme inhibition studies allowed the identification of novel indole-based inhibitors. The structural and inhibition studies reported here enhance the understanding of UGM-ligand interactions and will assist in the development of more potent inhibitors of UGM.en_US
dc.language.isoen_USen_US
dc.subjectsubstrate complexes and inhibitiorsen_US
dc.subjectcrystallographyen_US
dc.subjectUDP-galactopyranose mutaseen_US
dc.subjectcell wallen_US
dc.subjectgalactofuranoseen_US
dc.titleStructural and inhibition studies on UDP-galactopyranose mutaseen_US
thesis.degree.departmentChemistryen_US
thesis.degree.disciplineChemistryen_US
thesis.degree.grantorUniversity of Saskatchewanen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophy (Ph.D.)en_US
dc.type.materialtexten_US
dc.type.genreThesisen_US
dc.contributor.committeeMemberPedrasen_US
dc.contributor.committeeMemberReiden_US
dc.contributor.committeeMemberMosimann, Stevenen_US
dc.contributor.committeeMemberGrochulskien_US
dc.contributor.committeeMemberBaranskien_US


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