Sortase A as a novel molecular "stapler" for sequence-specific protein conjugation

Bioconjug Chem. 2007 Mar-Apr;18(2):469-76. doi: 10.1021/bc060339w. Epub 2007 Feb 16.


The Sortase family of transpeptidase enzymes catalyzes sequence-specific ligation of proteins to the cell wall of Gram-positive bacteria. Here, we describe the application of recombinant Staphylococcus aureus Sortase A to attach a tagged model protein substrate (green fluorescent protein) to polystyrene beads chemically modified with either alkylamine or the in vivo Sortase A ligand, Gly-Gly-Gly, on their surfaces. Furthermore, we show that Sortase A can be used to sequence-specifically ligate eGFP to amino-terminated poly(ethylene glycol) and to generate protein oligomers and cyclized monomers using suitably tagged eGFP. We find that an alkylamine can substitute for the natural Gly3 substrate, which suggests the possibility of using the enzyme in materials applications. The highly specific and mild Sortase A-catalyzed reaction, based on small recognition tags unlikely to interfere with protein expression, thus represents a useful addition to the protein immobilization and modification tool kit.

Publication types

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

MeSH terms

  • Amines / chemistry
  • Amines / metabolism
  • Aminoacyltransferases / metabolism*
  • Bacterial Proteins / metabolism*
  • Blotting, Western
  • Cell Wall / enzymology
  • Cysteine Endopeptidases / metabolism*
  • Escherichia / metabolism
  • Green Fluorescent Proteins / metabolism*
  • Oligopeptides / metabolism*
  • Polyethylene Glycols / chemistry
  • Polyethylene Glycols / metabolism
  • Polystyrenes / chemistry
  • Polystyrenes / metabolism
  • Recombinant Proteins / metabolism*
  • Staphylococcus aureus / enzymology


  • Amines
  • Bacterial Proteins
  • Oligopeptides
  • Polystyrenes
  • Recombinant Proteins
  • enhanced green fluorescent protein
  • Green Fluorescent Proteins
  • Polyethylene Glycols
  • glycyl-glycyl-glycine
  • Aminoacyltransferases
  • sortase A
  • Cysteine Endopeptidases