Biosynthesis of mycobacterial arabinogalactan: identification of a novel α(1→3) arabinofuranosyltransferase

Abstract

SummaryThe cell wall mycolyl-arabinogalactan-peptidoglycan complex is essential in mycobacterial species, such as Mycobacterium tuberculosis and is the target of several antitubercular drugs.

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

“…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. LM is converted to LAM by a series of ␣1-5-arabinosyltransferases, including EmbC (33,34), AftB, AftC (15), and AftD (5), and then capped with additional sugars or organic acids in pathogenic species (35,36).…”

Identification of a Terminal Rhamnopyranosyltransferase (RptA) Involved inCorynebacterium glutamicumCell Wall Biosynthesis

“…As a result, we have now termed this previously uncharacterized open reading frame, rhamnopyranosyltransferase A (rptA). Furthermore, an analysis of basestable extractable lipids from C. glutamicum revealed the presence of decaprenyl-monophosphorylrhamnose, a putative substrate for the cognate cell wall transferase.A common feature of members of the Corynebacterineae is that they possess an unusual cell wall dominated by a heteropolysaccharide termed an arabinogalactan (AG), which is linked to both mycolic acids and peptidoglycan, forming the mycolyl-arabinogalactan-peptidoglycan (mAGP) complex (5,10,12,15,24,25,34). The formation of the arabinan domain in the mAGP complex, consisting mainly of ␣135, ␣133, and ␤132 glycosyl linkages, results from the subsequent addition of arabinofuranose (Araf) from the lipid-linked sugar donor ␤-D-arabinofuranosyl-1-monophosphoryldecaprenol (DPA) by a set of unique membrane-bound arabinofuranosyltransferases (5,7,12,18,34).…”

“…The formation of the arabinan domain in the mAGP complex, consisting mainly of ␣135, ␣133, and ␤132 glycosyl linkages, results from the subsequent addition of arabinofuranose (Araf) from the lipid-linked sugar donor ␤-D-arabinofuranosyl-1-monophosphoryldecaprenol (DPA) by a set of unique membrane-bound arabinofuranosyltransferases (5,7,12,18,34).…”

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).…”