Oligomannoside biosynthesis in Mycobacterium smegmatis

Abstract

A cell-free particulate enzyme system of Mycobacterium smegmatis ATCC 607 was shown to catalyze the incorporation of labeled mannose from GDP-[ 14C]mannose into endogenous acceptors to form a series of labeled neutral oligomannosides. These oligomannosides were devoid of amino sugar. The major oligomannoside product was characterized to be a trimannoside, O-α- d-mannopyranosyl-(1 → 2)- O-α- d-mannopyranosyl(1 → 2)- d-mannose and represented 46% of the total labeled oligomannoside product. The higher oligomannosides were shown to have either/or both α(1 → 2) and α(1 → 6) glycosidic linkages. A series of unlabeled endogenous oligosaccharides was isolated from the 105,000g supernatant fractions of the cell-free extracts of M. smegmatis and found to be chromatographically similar to the labeled oligomannosides synthesized by the cell-free system. The nature of the endogenous acceptor was not determined.