Reaction: (1) GDP-α-D-mannose + 2-O-α-D-mannosyl-1-phosphatidyl-1D-myo-inositol = GDP + 2,6-di-O-α-D-mannosyl-1-phosphatidyl-1D-myo-inositol
(2) GDP-α-D-mannose + 2-O-(6-O-acyl-α-D-mannosyl)-1-phosphatidyl-1D-myo-inositol = GDP + 2-O-(6-O-acyl-α-D-mannosyl)-6-O-α-D-mannosyl-1-phosphatidyl-1D-myo-inositol
Glossary: 1-phosphatidyl-1D-myo-inositol = PtdIns
Other name(s): mannosyltransferase PimB; PimB; guanosine diphosphomannose-phosphatidyl-inositol α-mannosyltransferase (ambiguous)
Systematic name: GDP-α-D-mannose:2-O-α-D-mannosyl-1-phosphatidyl-1D-myo-inositol 6-α-D-mannosyltransferase (configuration-retaining)
Comments: Requires Mg2+. The enzyme, found in Corynebacteriales, is involved in the biosynthesis of phosphatidyl-myo-inositol mannosides (PIMs).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number:
References:
1. Guerin, M.E., Kaur, D., Somashekar, B.S., Gibbs, S., Gest, P., Chatterjee, D., Brennan, P.J. and Jackson, M. New insights into the early steps of phosphatidylinositol mannoside biosynthesis in mycobacteria: PimB' is an essential enzyme of Mycobacterium smegmatis. J. Biol. Chem. 284 (2009) 25687-25696. [PMID: 19638342]
2. Mishra, A.K., Batt, S., Krumbach, K., Eggeling, L. and Besra, G.S. Characterization of the Corynebacterium glutamicum Δ pimB' Δ mgtA double deletion mutant and the role of Mycobacterium tuberculosis orthologues Rv2188c and Rv0557 in glycolipid biosynthesis. J. Bacteriol. 191 (2009) 4465-4472. [PMID: 19395496]
3. Batt, S.M., Jabeen, T., Mishra, A.K., Veerapen, N., Krumbach, K., Eggeling, L., Besra, G.S. and Futterer, K. Acceptor substrate discrimination in phosphatidyl-myo-inositol mannoside synthesis: structural and mutational analysis of mannosyltransferase Corynebacterium glutamicum PimB'. J. Biol. Chem. 285 (2010) 37741-37752. [PMID: 20843801]