Theme E Highlights
Theme E supporting the wider biological sciences community.
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We have determined the crystal structure of the S. solfataricus KDG kinase to a resolution of 2.0Å, and a ternary complex with KDG and an ATP analogue to 2.1Å. The kinase forms a hexamer with 32 point group symmetry. The complex suggests that the structural basis for the enzyme’s ability to phosphorylate KDG and KDGal is derived from a subtle repositioning of residues that are conserved in homologous, non-promiscuous kinases. (submitted to JMB).
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Human quinolinate phosphoribosyltransferase is a member of the type II phosphoribosyltransferase family involved in the catabolism of quinolinic acid. It catalyses the formation of nicotinic acid mononucleotide from quinolinic acid, which involves a phosphoribosyl transfer reaction followed by decarboxylation. hQPRTase has been implicated in a number of neurological conditions and in order to study it further, we have carried out structural and kinetic studies on recombinant hQPRTase. The structure of the fully active enzyme overexpressed in E. coli was solved using multiwavelength methods to a resolution of 2.0 Å. PDB 2jbm (Collaboration with Nigel Botting, St Andrews)
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Cathsili (collaboration with Chris van der Walle, Strathclyde) Cathsili is a chimera of cathepsin-L that through the introduction of 16 mutations is changed from a protease to an enzyme with the ability to condense silica. The mutations are modelled on a sponge protein called silicatein which can condense silica and forms the glass structures that make up the sponges skeleton. In the reactions where cathsili condeses silica, silicilic acid is added to the protein, and after a few hours incubation a silica precipitate forms. Wild type cathepsin-L does not condense silica and gives no precipitate. The structure reveals a basis for the catalytic mechanism.
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| Serine palmitoyltransferase catalyses the formation of 3-ketosphinganine from serine and palmitoyl CoA. The apo structure was determined last year, we have now determined the holo enzyme (with PLP) 1.3 Å, an external aldamine (1.5 Å) and product complex 1.5 Å (collaboration with Dominic Campopiano Edinburgh). We have also solved the structure of a mutant enzyme which mimics a genetic defect found in the human enzyme.
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Although we have no new structural data. We have now resolved the chemistry of the novel co-factor found in Ranasmurfin (collaboration with Alan Cooper, Glasgow). The four residue cross link has a bridging nitrogen. |
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©Scottish Structural Proteomics Facility 2007.
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Updated:30-10-07 |
