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3bn1
From Proteopedia
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[[Image:3bn1.jpg|left|200px]] | [[Image:3bn1.jpg|left|200px]] | ||
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'''Crystal structure of GDP-perosamine synthase''' | '''Crystal structure of GDP-perosamine synthase''' | ||
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[[Category: Cook, P D.]] | [[Category: Cook, P D.]] | ||
[[Category: Holden, H M.]] | [[Category: Holden, H M.]] | ||
| - | [[Category: | + | [[Category: Aspartate aminotransferase]] |
| - | [[Category: | + | [[Category: Deoxysugar]] |
| - | [[Category: | + | [[Category: O-antigen]] |
| - | [[Category: | + | [[Category: Perosamine]] |
| - | [[Category: | + | [[Category: X-ray structure]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 20:55:21 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 17:55, 4 May 2008
Crystal structure of GDP-perosamine synthase
Overview
Perosamine or 4-amino-4,6-dideoxy- d-mannose is an unusual sugar found in the O-antigens of some Gram-negative bacteria such as Vibrio cholerae O1 (the causative agent of cholera) or Escherichia coli O157:H7 (the leading cause of food-borne illnesses). It and similar deoxysugars are added to the O-antigens of bacteria via the action of glycosyltransferases that employ nucleotide-linked sugars as their substrates. The focus of this report is GDP-perosamine synthase, a PLP-dependent enzyme that catalyzes the last step in the formation of GDP-perosamine, namely, the amination of the sugar C-4'. Here we describe the three-dimensional structure of the enzyme from Caulobacter crescentus determined to a nominal resolution of 1.8 A and refined to an R-factor of 17.9%. The overall fold of the enzyme places it into the well-characterized aspartate aminotransferase superfamily. Each subunit of the dimeric enzyme contains a seven-stranded mixed beta-sheet, a two-stranded antiparallel beta-sheet, and 12 alpha-helices. Amino acid residues from both subunits form the active sites of the GDP-perosamine synthase dimer. Recently, the structure of another PLP-dependent enzyme, GDP-4-keto-6-deoxy- d-mannose-3-dehydratase (or ColD), was determined in our laboratory, and this enzyme employs the same substrate as GDP-perosamine synthase. Unlike GDP-perosamine synthase, however, ColD functions as a dehydratase that removes the sugar C-3' hydroxyl group. By purifying the ColD product and reacting it with purified GDP-perosamine synthase, we have produced a novel GDP-linked sugar, GDP-4-amino-3,4,6-trideoxy- d-mannose. Details describing the X-ray structural investigation of GDP-perosamine synthase and the enzymatic synthesis of GDP-4-amino-3,4,6-trideoxy- d-mannose are presented.
About this Structure
3BN1 is a Single protein structure of sequence from Caulobacter vibrioides. Full crystallographic information is available from OCA.
Reference
GDP-Perosamine Synthase: Structural Analysis and Production of a Novel Trideoxysugar(,)., Cook PD, Holden HM, Biochemistry. 2008 Mar 4;47(9):2833-40. Epub 2008 Feb 5. PMID:18247575 Page seeded by OCA on Sun May 4 20:55:21 2008
