Cysteine misincorporation in bacterially expressed human alpha-synuclein

FEBS Lett. 2006 Mar 20;580(7):1775-9. doi: 10.1016/j.febslet.2006.02.032. Epub 2006 Feb 24.


Bacterially expressed human alpha-synuclein (alpha-syn) has been widely used in structural and functional studies. Here we show that approximately 20% of human alpha-syn expressed in Escherichia coli is mistranslated and that a Cys residue is incorporated at position 136 instead of a Tyr. Site-directed mutagenesis of codon 136 (TAC to TAT) resulted in the expression of alpha-syn lacking Cys. Although wild-type (Y136-TAC and Y136-TAT) and mutant (C136-TGC) alpha-syn had similar propensities to assemble into filaments, the levels of dimeric alpha-syn were increased by misincorporation. To avoid potential artefacts, we recommend use of the Y136-TAT construct for the expression of human alpha-syn.

MeSH terms

  • Amino Acid Sequence
  • Amino Acid Substitution*
  • Cloning, Molecular / methods*
  • Cysteine / metabolism*
  • Dimerization
  • Escherichia coli / genetics
  • Humans
  • Mutagenesis, Site-Directed
  • Protein Biosynthesis
  • alpha-Synuclein / genetics*


  • alpha-Synuclein
  • Cysteine