Three-dimensional structures of noncovalent complexes of Citrobacter freundii methionine γ-lyase with substrates

Biochemistry (Mosc). 2011 May;76(5):564-70. doi: 10.1134/S0006297911050063.


Crystal structures of Citrobacter freundii methionine γ-lyase complexes with the substrates of γ- (L-1-amino-3-methylthiopropylphosphinic acid) and β- (S-ethyl-L-cysteine) elimination reactions and the competitive inhibitor L-norleucine have been determined at 1.45, 1.8, and 1.63 Å resolution, respectively. All three amino acids occupy the active site of the enzyme but do not form a covalent bond with pyridoxal 5'-phosphate. Hydrophobic interactions between the active site residues and the side groups of the substrates and the inhibitor are supposed to cause noncovalent binding. Arg374 and Ser339 are involved in the binding of carboxyl groups of the substrates and the inhibitor. The hydroxyl of Tyr113 is a potential acceptor of a proton from the amino groups of the amino acids.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Binding Sites
  • Carbon-Sulfur Lyases / chemistry*
  • Carbon-Sulfur Lyases / genetics
  • Carbon-Sulfur Lyases / metabolism
  • Citrobacter freundii / chemistry
  • Citrobacter freundii / enzymology*
  • Citrobacter freundii / genetics
  • Cysteine / analogs & derivatives
  • Cysteine / chemistry
  • Enzyme Inhibitors / chemistry
  • Hydrophobic and Hydrophilic Interactions
  • Kinetics
  • Models, Molecular
  • Substrate Specificity


  • Bacterial Proteins
  • Enzyme Inhibitors
  • ethyl cysteine
  • Carbon-Sulfur Lyases
  • L-methionine gamma-lyase
  • Cysteine