Structure of a mycobacterial polysaccharide-fatty acyl-CoA complex: nuclear magnetic resonance studies.

MMP, a linear alpha 1 leads to 4 linked polymer of 3-O-methylmannose, regulates the fatty acid synthetase from Mycobacterium smegmatis by forming stoichiometric complexes with the long-chain acyl-CoA synthetase products. In agreement with previous proposals [Bloch, K. (1977) in Advances in Enzymology and Related Areas of Molecular Biology, ed. Meister, A. (Wiley, New York), Vol. 45, pp. 1-84], nuclear magnetic resonance studies show that the polysaccharide, a random coil in its free form, undergoes a major conformational transition upon enclosing long-chain acyl-CoA. The polysaccharide, probably in helical conformation in the complexed form, interacts with both the paraffinic chain and the CoA moieties of the included fatty acyl thioester.