Primary Citation of Related Structures: 2GEJ, 2GEK
PubMed Abstract:
Mycobacterial phosphatidylinositol mannosides (PIMs) and metabolically derived cell wall lipoglycans play important roles in host-pathogen interactions, but their biosynthetic pathways are poorly understood. Here we focus on Mycobacterium smegmatis PimA, an essential enzyme responsible for the initial mannosylation of phosphatidylinositol ...
Mycobacterial phosphatidylinositol mannosides (PIMs) and metabolically derived cell wall lipoglycans play important roles in host-pathogen interactions, but their biosynthetic pathways are poorly understood. Here we focus on Mycobacterium smegmatis PimA, an essential enzyme responsible for the initial mannosylation of phosphatidylinositol. The structure of PimA in complex with GDP-mannose shows the two-domain organization and the catalytic machinery typical of GT-B glycosyltransferases. PimA is an amphitrophic enzyme that binds mono-disperse phosphatidylinositol, but its transferase activity is stimulated by high concentrations of non-substrate anionic surfactants, indicating that the early stages of PIM biosynthesis involve lipid-water interfacial catalysis. Based on structural, calorimetric, and mutagenesis studies, we propose a model wherein PimA attaches to the membrane through its N-terminal domain, and this association leads to enzyme activation. Our results reveal a novel mode of phosphatidylinositol recognition and provide a template for the development of potential antimycobacterial compounds.
Related Citations:
Crystallization and preliminary crystallographic analysis of PimA, an essential mannosyltransferase from Mycobacterium smegmatis Guerin, M.E., Buschiazzo, A., Kordulakova, J., Jackson, M., Alzari, P.M. (2005) Acta Crystallogr Sect F Struct Biol Cryst Commun 61: 518
Definition of the first mannosylation step in phosphatidylinositol mannoside synthesis Kordulakova, J., Gilleron, M., Mikusova, K., Puzo, G., Brennan, P.J., Gicquel, B., Jackson, M. (2002) J Biol Chem 277: 31335
Mycbacterial lipoarabinomannan and related lipoglycans: from biogenesis to modulation of the immune response Briken, V., Porcelli, S.A., Besra, G.S., Kremer, L. (2004) Mol Microbiol 53: 391
Lipoarabinomannans: from structure to biosynthesis Nigou, J., Gilleron, M., Puzo, G. (2003) Biochimie 85: 153
An evolving hierarchical family classification for glycosyltransferases Coutinho, P.M., Deleury, E., Davies, G.J., Henrissat, B. (2003) J Mol Biol 328: 307
Organizational Affiliation:
Unité de Biochimie Structurale (CNRS URA 2185), Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France.
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