3GR9

Crystal structure of ColD H188K S187N

Summary for 3GR9

• Entry DOI: 10.2210/pdb3gr9/pdb
• Descriptor: ColD, 2-OXOGLUTARIC ACID (3 entities in total)
• Functional Keywords: colitose, perosamine, plp, aminotransferase, o-antigen, lipopolysaccharide, transferase
• Biological source: Escherichia coli
• Total number of polymer chains: 8
• Total formula weight: 357665.37

Authors

Holden, H.M.,Cook, P.D.,Kubiak, R.L.,Toomey, D.P. (deposition date: 2009-03-25, release date: 2009-06-16, Last modification date: 2023-11-22)

Primary citation

Cook, P.D.,Kubiak, R.L.,Toomey, D.P.,Holden, H.M.
Two Site-Directed Mutations Are Required for the Conversion of a Sugar Dehydratase into an Aminotransferase.
Biochemistry, 48:5246-5253, 2009

PubMed Abstract: L-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.

PubMed: 19402712
DOI: 10.1021/bi9005545

Experimental method

X-RAY DIFFRACTION (2.2 Å)