3gr9
Crystal structure of ColD H188K S187N
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedL-colitose and d-perosamine are unusual sugars found in the O-antigens of some Gram-negative bacteria such as Escherichia coli, Vibrio cholerae, and Salmonella enterica, among others. The biosynthetic pathways for these two sugars begin with the formation of GDP-mannose from d-mannose 1-phosphate and GTP followed by the subsequent dehydration and oxidation of GDP-mannose to yield GDP-4-keto-6-deoxymannose. Following the production of GDP-4-keto-6-deoxymannose, the two pathways diverge. In the case of GDP-perosamine biosynthesis, the next step involves an amination reaction at the C-4' position of the sugar, whereas in GDP-colitose production, the 3'-hydroxyl group is removed. The enzymes catalyzing these reactions are GDP-perosamine synthase and GDP-4-keto-6-deoxymannose-3-dehydratase (ColD), respectively. Both of these enzymes are pyridoxal 5'-phosphate (PLP) dependent, and their three-dimensional structures place them into the well-characterized aspartate aminotransferase superfamily. A comparison of the active site architecture of ColD from E. coli (strain 5a, type O55:H7) to that of GDP-perosamine synthase from Caulobacter crescentus CB15 suggested that only two mutations would be required to convert ColD into an aminotransferase. Here we present a combined structural and functional analysis of the ColD S187N/H188K mutant protein that, indeed, has been converted from a sugar dehydratase into an aminotransferase. Two site-directed mutations are required for the conversion of a sugar dehydratase into an aminotransferase.,Cook PD, Kubiak RL, Toomey DP, Holden HM Biochemistry. 2009 Jun 16;48(23):5246-53. PMID:19402712[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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