1g1a: Difference between revisions

Revision as of 17:00, 2 May 2008

THE CRYSTAL STRUCTURE OF DTDP-D-GLUCOSE 4,6-DEHYDRATASE (RMLB)FROM SALMONELLA ENTERICA SEROVAR TYPHIMURIUM

OverviewOverview

l-Rhamnose is a 6-deoxyhexose that is found in a variety of different glycoconjugates in the cell walls of pathogenic bacteria. The precursor of l-rhamnose is dTDP-l-rhamnose, which is synthesised from glucose- 1-phosphate and deoxythymidine triphosphate (dTTP) via a pathway requiring four enzymes. Significantly this pathway does not exist in humans and all four enzymes therefore represent potential therapeutic targets. dTDP-D-glucose 4,6-dehydratase (RmlB; EC 4.2.1.46) is the second enzyme in the dTDP-L-rhamnose biosynthetic pathway. The structure of Salmonella enterica serovar Typhimurium RmlB had been determined to 2.47 A resolution with its cofactor NAD(+) bound. The structure has been refined to a crystallographic R-factor of 20.4 % and an R-free value of 24.9 % with good stereochemistry.RmlB functions as a homodimer with monomer association occurring principally through hydrophobic interactions via a four-helix bundle. Each monomer exhibits an alpha/beta structure that can be divided into two domains. The larger N-terminal domain binds the nucleotide cofactor NAD(+) and consists of a seven-stranded beta-sheet surrounded by alpha-helices. The smaller C-terminal domain is responsible for binding the sugar substrate dTDP-d-glucose and contains four beta-strands and six alpha-helices. The two domains meet to form a cavity in the enzyme. The highly conserved active site Tyr(167)XXXLys(171) catalytic couple and the GlyXGlyXXGly motif at the N terminus characterise RmlB as a member of the short-chain dehydrogenase/reductase extended family.The quaternary structure of RmlB and its similarity to a number of other closely related short-chain dehydrogenase/reductase enzymes have enabled us to propose a mechanism of catalysis for this important enzyme.

About this StructureAbout this Structure

1G1A is a Single protein structure of sequence from Salmonella enterica. Full crystallographic information is available from OCA.

ReferenceReference

The crystal structure of dTDP-D-Glucose 4,6-dehydratase (RmlB) from Salmonella enterica serovar Typhimurium, the second enzyme in the dTDP-l-rhamnose pathway., Allard ST, Giraud MF, Whitfield C, Graninger M, Messner P, Naismith JH, J Mol Biol. 2001 Mar 16;307(1):283-95. PMID:11243820 Page seeded by OCA on Fri May 2 17:00:25 2008

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OCA

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 [[Image:1g1a.gif|left|200px]]
- {{Structure
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-}}
 '''THE CRYSTAL STRUCTURE OF DTDP-D-GLUCOSE 4,6-DEHYDRATASE (RMLB)FROM SALMONELLA ENTERICA SEROVAR TYPHIMURIUM'''
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 [[Category: Salmonella enterica]]
 [[Category: Single protein]]
-[[Category: dTDP-glucose 4,6-dehydratase]]
+[[Category: DTDP-glucose 4,6-dehydratase]]
 [[Category: Allard, S T.M.]]
 [[Category: Giraud, M F.]]
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 [[Category: Naismith, J H.]]
 [[Category: Whitfield, C.]]
-[[Category: protein-nad complex]]
+[[Category: Protein-nad complex]]
-[[Category: rossmann fold]]
+[[Category: Rossmann fold]]
-[[Category: short chain dehydrogenase]]
+[[Category: Short chain dehydrogenase]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 17:00:25 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 20:34:30 2008''