New insights into the early steps of phosphatidylinositol mannoside biosynthesis in mycobacteria: PimB' is an essential enzyme of Mycobacterium smegmatis.

ABSTRACT: Phosphatidyl-myo-inositol mannosides (PIMs) are key glycolipids of the mycobacterial cell envelope. They are considered not only essential structural components of the cell but also important molecules implicated in host-pathogen interactions. Although their chemical structures are well established, knowledge of the enzymes and sequential events leading to their biosynthesis is still incomplete. Here we show for the first time that although both mannosyltransferases PimA and PimB' (MSMEG_4253) recognize phosphatidyl-myo-inositol (PI) as a lipid acceptor, PimA specifically catalyzes the transfer of a Manp residue to the 2-position of the myo-inositol ring of PI, whereas PimB' exclusively transfers to the 6-position. Moreover, whereas PimB' can catalyze the transfer of a Manp residue onto th

SUBMITTER: Guerin ME 

PROVIDER: S-EPMC2757970 | biostudies-literature | 2009 Sep

REPOSITORIES: biostudies-literature