3okc
From Proteopedia
Crystal structure of Corynebacterium glutamicum PimB' bound to GDP (orthorhombic crystal form)
Structural highlights
Function[PIMB_CORGL] Catalyzes the addition of a mannose residue from GDP-D-mannose to the position 6 of a phosphatidyl-myo-inositol bearing an alpha-1,2-linked mannose residue (PIM1) to generate phosphatidyl-myo-inositol bearing alpha-1,2- and alpha-1,6-linked mannose residues (PIM2). Can also add a mannose residue to the position 2 of a phosphatidyl-myo-inositol (PI) to generate a phosphatidyl-myo-inositol mannoside (PIM1). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedLong term survival of the pathogen Mycobacterium tuberculosis in humans is linked to the immunomodulatory potential of its complex cell wall glycolipids, which include the phosphatidylinositol mannoside (PIM) series as well as the related lipomannan and lipoarabinomannan glycoconjugates. PIM bioynthesis is initiated by a set of cytosolic alpha-mannosyltransferases, catalysing glycosyl transfer from the activated saccharide donor GDP-Man to the acceptor phosphatidyl-myo-inositol (PI) in an ordered and regio-specific fashion. Herein, we report the crystal structure of mannosyltransferase C. glutamicum PimB' in complex with nucleotide to a resolution of 2.0 A. PimB' attaches mannosyl selectively to the 6-OH of the inositol moiety of PI. Two crystal forms and GDP- versus GDP-Man-bound complexes reveal flexibility of the nucleotide conformation as well as of the structural framework of the active site. Structural comparison, docking of the saccharide acceptor and site directed mutagenesis pin regio-selectivity to a conserved Asp residue in the N-terminal domain that forces presentation of the correct inositol hydroxyl to the saccharide donor. Acceptor substrate discrimination in phosphatidyl-myo-inositol mannoside synthesis: Structural and mutational analysis of mannosyltransferase Corynebacterium glutamicum PimB',Batt SM, Jabeen T, Mishra AK, Veerapen N, Krumbach K, Eggeling L, Besra GS, Futterer K J Biol Chem. 2010 Sep 15. PMID:20843801[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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