AglP is a S-adenosyl-L-methionine-dependent methyltransferase that participates in the N-glycosylation pathway of Haloferax volcanii

Mol Microbiol. 2010 Apr;76(1):190-9. doi: 10.1111/j.1365-2958.2010.07090.x. Epub 2010 Feb 10.


While pathways for N-glycosylation in Eukarya and Bacteria have been solved, considerably less is known of this post-translational modification in Archaea. In the halophilic archaeon Haloferax volcanii, proteins encoded by the agl genes are involved in the assembly and attachment of a pentasaccharide to select asparagine residues of the S-layer glycoprotein. AglP, originally identified based on the proximity of its encoding gene to other agl genes whose products were shown to participate in N-glycosylation, was proposed, based on sequence homology, to serve as a methyltransferase. In the present report, gene deletion and mass spectrometry were employed to reveal that AglP is responsible for adding a 14 Da moiety to a hexuronic acid found at position four of the pentasaccharide decorating the Hfx. volcanii S-layer glycoprotein. Subsequent purification of a tagged version of AglP and development of an in vitro assay to test the function of the protein confirmed that AglP is a S-adenosyl-L-methionine-dependent methyltransferase.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Archaeal Proteins / genetics
  • Archaeal Proteins / isolation & purification
  • Archaeal Proteins / metabolism*
  • Gene Deletion
  • Glycosylation*
  • Haloferax volcanii / enzymology*
  • Haloferax volcanii / genetics
  • Hexuronic Acids / metabolism
  • Mass Spectrometry
  • Methyltransferases / genetics
  • Methyltransferases / isolation & purification
  • Methyltransferases / metabolism*
  • Selenomethionine / analogs & derivatives*
  • Selenomethionine / metabolism


  • Archaeal Proteins
  • Hexuronic Acids
  • adenosylselenomethionine
  • Selenomethionine
  • Methyltransferases