Glutamine-linked and non-consensus asparagine-linked oligosaccharides present in human recombinant antibodies define novel protein glycosylation motifs

J Biol Chem. 2010 May 21;285(21):16012-22. doi: 10.1074/jbc.M109.096412. Epub 2010 Mar 16.

Abstract

We report the presence of oligosaccharide structures on a glutamine residue present in the V(L) domain sequence of a recombinant human IgG2 molecule. Residue Gln-106, present in the QGT sequence following the rule of an asparagine-linked consensus motif, was modified with biantennary fucosylated oligosaccharide structures. In addition to the glycosylated glutamine, analysis of a lectin-enriched antibody population showed that 4 asparagine residues: heavy chain Asn-162, Asn-360, and light chain Asn-164, both of which are present in the IgG1 and IgG2 constant domain sequences, and Asn-35, which was present in CDR(L)1, were also modified with oligosaccharide structures at low levels. The primary sequences around these modified residues do not adhere to the N-linked consensus sequon, NX(S/T). Modeling of these residues from known antibody crystal structures and sequence homology comparison indicates that non-consensus glycosylation occurs on Asn residues in the context of a reverse consensus motif (S/T)XN located on highly flexile turns within 3 residues of a conformational change. Taken together our results indicate that protein glycosylation is governed by more diversified requirements than previously appreciated.

MeSH terms

  • Antibodies, Monoclonal / chemistry*
  • Antibodies, Monoclonal / genetics
  • Antibodies, Monoclonal / immunology
  • Asparagine / chemistry*
  • Asparagine / genetics
  • Asparagine / immunology
  • Glutamic Acid / chemistry*
  • Glutamic Acid / genetics
  • Glutamic Acid / immunology
  • Glycosylation
  • Humans
  • Immunoglobulin G / chemistry*
  • Immunoglobulin G / genetics
  • Immunoglobulin G / immunology
  • Models, Molecular
  • Oligosaccharides / chemistry*
  • Oligosaccharides / genetics
  • Oligosaccharides / immunology
  • Protein Modification, Translational*
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / immunology

Substances

  • Antibodies, Monoclonal
  • Immunoglobulin G
  • Oligosaccharides
  • Recombinant Proteins
  • Glutamic Acid
  • Asparagine