Role of a single amino acid in the evolution of glycans of invertebrates and vertebrates.

ABSTRACT: Structures of glycoconjugate N-glycans and glycolipids of invertebrates show significant differences from those of vertebrates. These differences are due largely to the vertebrate beta1,4-galactosyltransferase-1 (beta4Gal-T1), which is found as a beta1,4-N-acetylgalactosaminyltransferase (beta4GalNAc-T1) in invertebrates. Mutation of Tyr285 to Ile or Leu in human beta4Gal-T1 converts the enzyme into an equally efficient beta4GalNAc-T1. A comparison of all the human beta4Gal-T1 ortholog enzymes shows that this Tyr285 residue in human beta4Gal-T1 is conserved either as Tyr or Phe in all vertebrate enzymes, while in all invertebrate enzymes it is conserved as an Ile or Leu. We find that mutation of the corresponding Ile residue to Tyr in Drosophila beta4GalNAc-T1 converts the enzyme to a beta

SUBMITTER: Ramakrishnan B 

PROVIDER: S-EPMC1850938 | biostudies-literature | 2007 Jan

REPOSITORIES: biostudies-literature