1mc3
From Proteopedia
CRYSTAL STRUCTURE OF RFFH
Structural highlights
FunctionRMLA2_ECOLI Catalyzes the formation of dTDP-glucose, from dTTP and glucose 1-phosphate, as well as its pyrophosphorolysis. Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe enzyme glucose-1-phosphate thymidylyltransferase (RffH), the product of the rffh gene, catalyzes one of the steps in the synthesis of enterobacterial common antigen (ECA), a cell surface glycolipid found in Gram-negative enteric bacteria. In Escherichia coli two gene products, RffH and RmlA, catalyze the same enzymatic reaction and are homologous in sequence; however, they are part of different operons and function in different pathways. We report the crystal structure of RffH bound to deoxythymidine triphosphate (dTTP), the phosphate donor, and Mg(2+), refined at 2.6 A to an R-factor of 22.3% (R(free) = 28.4%). The crystal structure of RffH shows a tetrameric enzyme best described as a dimer of dimers. Each monomer has an overall alpha/beta fold and consists of two domains, a larger nucleotide binding domain (residues 1-115, 222-291) and a smaller sugar-binding domain (116-221), with the active site located at the domain interface. The Mg(2+) ion is coordinated by two conserved aspartates and the alpha-phosphate of deoxythymidine triphosphate. Its location corresponds well to that in a structurally similar domain of N-acetylglucosamine-1-phosphate uridylyltransferase (GlmU). Analysis of the RffH, RmlA, and GlmU complexes with substrates and products provides an explanation for their different affinities for Mg(2+) and leads to a proposal for the dynamics along the reaction pathway. Crystal structure of Escherichia coli glucose-1-phosphate thymidylyltransferase (RffH) complexed with dTTP and Mg2+.,Sivaraman J, Sauve V, Matte A, Cygler M J Biol Chem. 2002 Nov 15;277(46):44214-9. Epub 2002 Aug 8. PMID:12171937[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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