Identification of a novel α(1→6) mannopyranosyltransferase MptB from Corynebacterium glutamicum by deletion of a conserved gene, NCgl1505, affords a lipomannan‐ and lipoarabinomannan‐deficient mutant

Abstract

SummaryMycobacterium tuberculosis and Corynebacterium glutamicum share a similar cell wall structure and orthologous enzymes involved in cell wall assembly. Herein, we have studied C. glutamicum NCgl1505, the orthologue of putative glycosyltransferases Rv1459c from M. tuberculosis and MSMEG3120 from

Identification of a Membrane Protein Required for Lipomannan Maturation and Lipoarabinomannan Synthesis in Corynebacterineae

“…However, our findings indicate that NCgl2760 influences both the LM-A and LM-B pathways. This is also the case for a number of previously characterized GT-C type mannosyltransferases involved in synthesis of the mannan backbone and mannose side branches (12,17,31), showing that the same reactions occur on different lipid anchors. It remains unclear why LM-B species fail to progress further down the pathway to form LAMs.…”

“…These acylated PIM2 species can undergo additional mannosylation to form acylated PIM6 as an end product or to form hyperglycosylated LM and LAM in periplasmic reactions requiring polyprenol phosphomannose (PPM) donors. In mycobacteria, PimE uses PPM to elongate a population of AcPIM4 to form AcPIM6 (28), whereas studies in C. glutamicum show that MptB serves as the ␣1-6-mannosyltransferase that extends AcPIM2 to form the initial mannan backbone of LM (17) following its activation by lipoprotein LpqW (29,30). However, the role of MptB in mycobacteria is unclear, possibly due to gene redundancy (17).…”

“…In mycobacteria, PimE uses PPM to elongate a population of AcPIM4 to form AcPIM6 (28), whereas studies in C. glutamicum show that MptB serves as the ␣1-6-mannosyltransferase that extends AcPIM2 to form the initial mannan backbone of LM (17) following its activation by lipoprotein LpqW (29,30). However, the role of MptB in mycobacteria is unclear, possibly due to gene redundancy (17). PPM-dependent mannosyltransferases MptC and MptD add ␣1-2-mannose side chains (31) essential for virulence (32), whereas further extension of the ␣1-6 backbone is performed by MptA (12), forming LM.…”

“…Although both pathways share many common enzymes, LM-A species are based on a glucopyranosyluronic acid diacylglycerol (Gl-A) anchor rather than PI (16,18). On the cytoplasmic side, Gl-A is mannosylated by MgtA (previously named PimB), producing mannosyl-glucuronic acid diacylglycerol (Gl-X), which is extended by MptB (17,29) and other enzymes common to both pathways to produce LM-B, the major LM pool of C. glutamicum (37,38).…”

Deletion of manC in Corynebacterium glutamicum results in a phospho-myo-inositol mannoside- and lipoglycan-deficient mutant

“…Consequently, a comprehensive analysis of the role of these enzymes in cell wall biogenesis has always been limited. In such a scenario, the use of the easily cultivable and non-pathogenic C. glutamicum has been very useful, especially in terms of otherwise essential genes in mycobacteria, involved in the biosynthesis of mycolic acids (Gande et al, 2004(Gande et al, , 2007, arabinogalactan (Alderwick et al, 2006a(Alderwick et al, , b, 2007Birch et al, 2008;Seidel et al, 2007) and LAM (Gibson et al, 2003;Mishra et al, 2007Mishra et al, , 2008aMishra et al, , b, 2009Mishra et al, , 2011aTatituri et al, 2007a, b).…”