Transamidase subunit GAA1/GPAA1 is a M28 family metallo-peptide-synthetase that catalyzes the peptide bond formation between the substrate protein's omega-site and the GPI lipid anchor's phosphoethanolamine

Cell Cycle. 2014;13(12):1912-7. doi: 10.4161/cc.28761. Epub 2014 Apr 17.

Abstract

The transamidase subunit GAA1/GPAA1 is predicted to be the enzyme that catalyzes the attachment of the glycosylphosphatidyl (GPI) lipid anchor to the carbonyl intermediate of the substrate protein at the ω-site. Its ~300-amino acid residue lumenal domain is a M28 family metallo-peptide-synthetase with an α/β hydrolase fold, including a central 8-strand β-sheet and a single metal (most likely zinc) ion coordinated by 3 conserved polar residues. Phosphoethanolamine is used as an adaptor to make the non-peptide GPI lipid anchor look chemically similar to the N terminus of a peptide.

Keywords: GAA1; GPAA1; GPI lipid anchor; GPI transamidase; M28 peptidase; metallo-peptide-synthetase; protein sequence; sequence analysis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aminoacyltransferases / chemistry
  • Aminoacyltransferases / metabolism*
  • Ethanolamines / metabolism*
  • Glycosylphosphatidylinositols / metabolism*
  • Humans
  • Membrane Glycoproteins / chemistry
  • Membrane Glycoproteins / metabolism*
  • Peptide Synthases / metabolism*
  • Peptides / chemistry*
  • Protein Carbonylation
  • Protein Subunits / chemistry
  • Protein Subunits / metabolism*

Substances

  • Ethanolamines
  • GPAA1 protein, human
  • Glycosylphosphatidylinositols
  • Membrane Glycoproteins
  • Peptides
  • Protein Subunits
  • phosphorylethanolamine
  • Aminoacyltransferases
  • transamidases
  • Peptide Synthases