Structure Report for: 4H18

Huc, E., de Sousa-D'Auria, C., de la Sierra-Gallay, I.L., Salmeron, C., van Tilbeurgh, H., Bayan, N., Houssin, C., Daffe, M., Tropis, M

Title: Identification of a mycoloyl transferase selectively involved in O-acylation of polypeptides in Corynebacteriales
Huc E, de Sousa-D'Auria C, de la Sierra-Gallay IL, Salmeron C, van Tilbeurgh H, Bayan N, Houssin C, Daffe M, Tropis M
Ref: Journal of Bacteriology, 195:4121, 2013 : PubMed
Abstract


ESTHER: Huc_2013_J.Bacteriol_195_4121
PubMedSearch: Huc 2013 J.Bacteriol 195 4121
PubMedID: 23852866
Gene_locus related to this paper: corgl-CGL0343

Abstract

We have previously described the posttranslational modification of pore-forming small proteins of Corynebacterium by mycolic acid, a very-long-chain alpha-alkyl and beta-hydroxy fatty acid. Using a combination of chemical analyses and mass spectrometry, we identified the mycoloyl transferase (Myt) that catalyzes the transfer of the fatty acid residue to yield O-acylated polypeptides. Inactivation of corynomycoloyl transferase C (cg0413 [Corynebacterium glutamicum mytC {CgmytC}]), one of the six Cgmyt genes of C. glutamicum, specifically abolished the O-modification of the pore-forming proteins PorA and PorH, which is critical for their biological activity. Expectedly, complementation of the cg0413 mutant with either the wild-type gene or its orthologues from Corynebacterium diphtheriae and Rhodococcus, but not Nocardia, fully restored the O-acylation of the porins. Consistently, the three-dimensional structure of CgMytC showed the presence of a unique loop that is absent from enzymes that transfer mycoloyl residues onto both trehalose and the cell wall arabinogalactan. These data suggest the implication of this structure in the enzyme specificity for protein instead of carbohydrate.