Cyclodextrin glycosyltransferase (CGTase) uses ana-retain-ingdoubledisplacementmechanismtocatalyze threedistinct transglycosylation reactions. To investigate these reactions as catalyzed by the CGTase fromThermoanaerobacterium thermosulfurigenesthe enzyme was overproduced (8 mgÆL )1 culture) usingBacillus subtilisas a host. Detailed analysis revealed that the three reactions proceed via different kinetic mechanisms.

Saccharomyces cerevisiaeGpi3p is the UDP-GlcNAc-bind-ing andpresumed catalytic subunit of the enzyme that forms GlcNAc-phosphatidylinositol in glycosylphosphatidylinosi-tol biosynthesis. It is anessential proteinwithanEX7 Emotif that is conserved in four families of retaining glycosyl-transferases. All Gpi3ps contain a cysteine residue four residues C-terminal to EX7E. To test their importance for Gpi3p functionin vivo,Glu289 and297 in theEX7 Emotif of S. cerevisiaeGpi3p, as well as Cys301, were altered by site-specificmutagenesis, and themutant proteins tested for their ability to complement nonviable GPI3-deleted haploids....

The dihydrochalcone phlorizin (phloretin 2¢-glucoside) contributes to the flavor, color and health benefits of apple fruit and processed products. A genomics approach was used to identify the geneMdPGT1in apple (Ma-lus x domestica) with homology to the UDP-glycosyltransferase 88 family of uridine diphosphate glycosyltransferases that show specificity towards flavonoid substrates.

UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferases (GalNAc transferases), which initiate mucin-type O-glycan biosynthesis, have broad acceptor substrate specificities, and it is still unclear how they recognize peptides with different sequences.

Cell wall biosynthesis is a key target for antibacterial drugs. The major constituent of the bacterial wall, peptidoglycan, is a netlike polymer responsible for the size and shape of the cell and for resisting osmotic pres-sure. It consists of glycan chains of repeating disaccharide units cross-linked through short peptide chains.