title: Conservative replacement of methionine by norleucine in Escherichia coli adenylate kinase.
abstract: Escherichia coli grown in limited methionine and excess norleucine media accumulate cyanogen bromide-resistant species of proteins after the methionine supply is exhausted. Bacteria, transformed by recombinant plasmid pIPD37 carrying the adk gene and grown under limiting methionine and excess norleucine, synthesize 16-20% of adenylate kinase molecules having all 6 methionine residues replaced by norleucine. Species showing only partial replacement of methionine residues by norleucine are identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis after cyanogen bromide treatment of pure enzyme. Norleucine-substituted adenylate kinase shows structural and catalytic properties similar to the wild-type protein as indicated by circular dichroism spectroscopy and kinetic experiments but exhibits a much higher resistance to hydrogen peroxide inactivation under denaturing conditions.
authors.affiliation: Unité de Chimie des Protéines, Institut Pasteur, Paris, France.
authors.forename: A M
authors.initials: AM
authors.lastname: Gilles
authors.forename: P
authors.initials: P
authors.lastname: Marlière
authors.forename: T
authors.initials: T
authors.lastname: Rose
authors.forename: R
authors.initials: R
authors.lastname: Sarfati
authors.forename: R
authors.initials: R
authors.lastname: Longin
authors.forename: A
authors.initials: A
authors.lastname: Meier
authors.forename: S
authors.initials: S
authors.lastname: Fermandjian
authors.forename: M
authors.initials: M
authors.lastname: Monnot
authors.forename: G N
authors.initials: GN
authors.lastname: Cohen
authors.forename: O
authors.initials: O
authors.lastname: Bârzu
mesh_terms: D000249:Adenosine Monophosphate / Q000494:pharmacology; D000263:Adenylate Kinase / Q000032:analysis*; D000596:Amino Acids / Q000032:analysis; D000614:Aminocaproates; D002942:Circular Dichroism; D003488:Cyanogen Bromide / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007700:Kinetics; D008715:Methionine; D009646:Norleucine; D010770:Phosphotransferases / Q000032:analysis*; D013329:Structure-Activity Relationship
chemical_list: D000596:Amino Acids; D000614:Aminocaproates; D000249:Adenosine Monophosphate; D009646:Norleucine; D008715:Methionine; D006861:Hydrogen Peroxide; D010770:Phosphotransferases; D000263:Adenylate Kinase; D003488:Cyanogen Bromide