Partial redundancy in the synthesis of the D-arabinose incorporated in the cell wall arabinan of Corynebacterineae. - Archive ouverte HAL
Article Dans Une Revue Microbiology Année : 2008

Partial redundancy in the synthesis of the D-arabinose incorporated in the cell wall arabinan of Corynebacterineae.

Xavier Meniche
  • Fonction : Auteur
Benoît van Der Rest
  • Fonction : Auteur
Suresh Bhamidi
  • Fonction : Auteur
Emilie Huc
  • Fonction : Auteur
Hairong Huang
  • Fonction : Auteur
Diane de Paepe
  • Fonction : Auteur
Marielle Tropis
  • Fonction : Auteur
Mike Mcneil
  • Fonction : Auteur
Mamadou Daffé
  • Fonction : Auteur

Résumé

The major cell wall carbohydrate of Corynebacterineae is arabinogalactan (AG), a branched polysaccharide that is essential for the physiology of these bacteria. Decaprenylphosphoryl-D-arabinose (DPA), the lipid donor of D-arabinofuranosyl residues of AG, is synthesized through a series of unique biosynthetic steps, the last one being the epimerization of decaprenylphosphoryl-beta-D-ribose (DPR) into DPA, which is believed to proceed via a sequential oxidation-reduction mechanism. Two proteins from Mycobacterium tuberculosis (Rv3790 and Rv3791) have been shown to catalyse this epimerization in an in vitro system. The present study addressed the exact function of these proteins through the inactivation of the corresponding orthologues in Corynebacterium glutamicum (NCgl0187 and NCgl0186, respectively) and the analysis of their in vivo effects on AG biosynthesis. We showed that NCgl0187 is essential, whereas NCgl0186 is not. Deletion of NCgl0186 led to a mutant possessing an AG that contained half the arabinose and rhamnose, and less corynomycolates linked to AG but more trehalose mycolates, compared with the parental strain. A candidate gene that may encode a protein functionally similar to NCgl0186 was identified in both C. glutamicum (NCgl1429) and M. tuberculosis (Rv2073c). While the deletion of NCgl1429 had no effect on AG biosynthesis of the mutant, the gene could complement the mycolate defect of the AG of the NCgl0186 mutant, strongly supporting the concept that the two proteins play a similar function in vivo. Consistent with this, the NCgl1429 gene appeared to be essential in the NCgl0186-inactivated mutant. A detailed bioinformatics analysis showed that NCgl1429, NCgl0186, Rv3791 and Rv2073c could constitute, with 52 other proteins belonging to the actinomycetales, a group of closely related short-chain reductases/dehydrogenases (SDRs) with atypical motifs. We propose that the epimerization of DPR to DPA involves three enzymes that catalyse two distinct steps, each being essential for the viability of the bacterial cells.

Dates et versions

hal-00354679 , version 1 (20-01-2009)

Identifiants

Citer

Xavier Meniche, Célia de Sousa-d'Auria, Benoît van Der Rest, Suresh Bhamidi, Emilie Huc, et al.. Partial redundancy in the synthesis of the D-arabinose incorporated in the cell wall arabinan of Corynebacterineae.. Microbiology, 2008, 154 (Pt 8), pp.2315-26. ⟨10.1099/mic.0.2008/016378-0⟩. ⟨hal-00354679⟩
40 Consultations
0 Téléchargements

Altmetric

Partager

More