Open AccessIdentification of the mycobacterial glucosyl‐3‐phosphoglycerate synthase
Author(s) -
Empadinhas Nuno,
Albuquerque Luciana,
Mendes Vitor,
MacedoRibeiro Sandra,
Da Costa Milton S.
Publication year - 2008
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2007.01064.x
Subject(s) - gene , glycosyltransferase , biochemistry , mycobacterium smegmatis , mycobacterium bovis , biology , mycobacterium , enzyme , escherichia coli , transferase , function (biology) , microbiology and biotechnology , actinobacteria , bacteria , genetics , mycobacterium tuberculosis , tuberculosis , 16s ribosomal rna , medicine , pathology
Mycobacteria synthesize unique polysaccharides that regulate fatty acid synthesis, namely the methylglucose lipopolysaccharide (MGLP) and the methylmannose polysaccharide. Glucosyl–(1→2)–glycerate is found at the reducing end of MGLP. The mycobacterial gene encoding a glucosyl‐3‐phosphoglycerate synthase (GpgS), primarily found in actinobacteria and sharing very low amino acid identity with known homo‐functional GpgSs, has been identified. This gene has been annotated as an inverting family 2 glycosyltransferase of unknown function. The gpgS genes from the fast‐growing Mycobacterium smegmatis strain 1102 and from the slow‐growing Mycobacterium bovis BCG in Escherichia coli were expressed, and the recombinant enzymes were purified and characterized. The substrates for optimal activity were UDP‐glucose and d ‐3‐phosphoglycerate but ADP–glucose was also an efficient donor. The enzymes had maximal activity around 45 °C, pH 8.0, and were strictly dependent on Mg 2+ . In Mycobacterium tuberculosis H37Rv, the gene encoding GpgS ( Rv1208 ) is identical to the homologue in Mycobacterium bovis BCG and was considered to be essential for growth. It is shown that these genes encode retaining family 81 glycosyltransferases regardless of the low amino acid identity with other known enzymes of this family.