Crystal structure of mutant form Cys115His of Citrobacter freundii methionine γ-lyase complexed with L-norleucine

Publication date: Available online 6 June 2017
Source:Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics
Author(s): Svetlana V. Revtovich, Elena A. Morozova, Vitalia V. Kulikova, Natalya V. Anufrieva, Tatyana I. Osipova, Vasiliy S. Koval, Alexey D. Nikulin, Tatyana V. Demidkina
The mutant form of Citrobacter freundii methionine γ-lyase with the replacement of active site Cys115 for His has been found to be inactive in the γ-elimination reaction of methionine while fully active in the γ-elimination reaction of O-acetyl-L-homoserine and in the β-elimination reaction of S-alk(en)yl-substituted cysteines. In this work, the crystal structure of the mutant enzyme complexed with competitive inhibitor, L-norleucine was determined at 1.45 Å resolution. At the enzyme active site the inhibitor proved to be bound both noncovalently and covalently, which corresponds to the two intermediates of the γ- and β-elimination reactions, Michaelis complex and the external aldimine. Analysis of the structure allowed us to suggest the possible reason for the inability of the mutant enzyme to catalyze the physiological reaction.



from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2s3y9Wg
via IFTTT