Phytanyl-pyrophosphate-linked substrate for a bacterial alpha-mannosyltransferase

The biochemical characterization of bacterial glycosyltransferases involved in the assembly of cell-wall-associated polysaccharides is often hindered by the lack of the appropriate undecaprenyl-pyrophosphate-linked acceptor s ubstrate. In order to find a suitable synthetic substrate for the alpha 1,3 -mannosyltransferase AceA from Acetobacter xylinum, phytanyl-pyrophosphate- linked cellobiose was prepared. In the presence of GDP[C-14]mannose and rec ombinant AceA, the phytanyl-pyrophosphate-linked cellobiose afforded a C-14 -labeled trisaccharide that was sensitive to alpha-mannosidase degradation in a fashion analogous to the natural undecaprenyl-pyrophosphate-linked cel lobiose substrate. These results suggest that phytanyl-pyrophosphate-linked oligosaccharides may be useful substrates for other important bacterial gl ycosyltransferases. (C) 2000 Academic Press.