Structure-based evolutionary relationship of glycosyltransferases: a case study of vertebrate ?1,4-galactosyltransferase, invertebrate ?1,4-N-acetylgalactosaminyltransferase and ?-polypeptidyl-N-acetylgalactosaminyltransferase.

ABSTRACT: Cell surface glycans play important cellular functions and are synthesized by glycosyltransferases. Structure and function studies show that the donor sugar specificity of the invertebrate ?1,4-N-acetyl-glactosaminyltransferase (?4GalNAc-T) and the vertebrate ?1,4-galactosyltransferase I (?4Gal-T1) are related by a single amino acid residue change. Comparison of the catalytic domain crystal structures of the ?4Gal-T1 and the ?-polypeptidyl-GalNAc-T (?ppGalNAc-T) shows that their protein structure and sequences are similar. Therefore, it seems that the invertebrate ?4GalNAc-T and the catalytic domain of ?ppGalNAc-T might have emerged from a common primordial gene. When vertebrates emerged from invertebrates, the amino acid that determines the donor sugar specificity of the invertebrate ?4GalNAc-T might have mutated, thus converting the enzyme to a ?4Gal-T1 in vertebrates.

SUBMITTER: Ramakrishnan B 

PROVIDER: S-EPMC2974045 | biostudies-literature | 2010 Oct

REPOSITORIES: biostudies-literature