title: Substrate specificity of L-delta-(alpha-aminoadipoyl)-L-cysteinyl-D-valine synthetase from Cephalosporium acremonium: demonstration of the structure of several unnatural tripeptide products.
abstract: Potential substrates for L-delta-(alpha-aminoadipoyl)-L-(cysteinyl)-D-valine (ACV) synthetase were initially identified using both the amino-acid-dependent ATP<-->pyrophosphate exchange reaction catalysed by the enzyme and the incorporation of 14C-radiolabelled cysteine and valine into potential peptide products. S-Carboxymethylcysteine was an effective substitute for alpha-aminoadipate and both allylglycine and vinylglycine could substitute for cysteine, indicating that the thiol group of cysteine is not essential for peptide formation. L-allo-Isoleucine but not L-isoleucine substituted effectively for valine. The structures of the presumed peptide products derived from these amino acids were confirmed by combined use of electrospray-ionization m.s. (e.s.m.s.) and 1H n.m.r. These results clearly indicate that, in common with other peptide synthetases, but in contrast with ribosomal peptide synthesis, ACV synthetase has a relatively broad substrate specificity.
authors.affiliation: Oxford Centre for Molecular Sciences, U.K.
authors.forename: J E
authors.initials: JE
authors.lastname: Baldwin
authors.forename: C Y
authors.initials: CY
authors.lastname: Shiau
authors.forename: M F
authors.initials: MF
authors.lastname: Byford
authors.forename: C J
authors.initials: CJ
authors.lastname: Schofield
mesh_terms: D015074:2-Aminoadipic Acid / Q000378:metabolism; D000164:Acremonium / Q000201:enzymology*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000501:Allylglycine / Q000378:metabolism; D002233:Carbocysteine / Q000378:metabolism; D002250:Carbon Radioisotopes; D003545:Cysteine / Q000378:metabolism; D005998:Glycine / Q000031:analogs & derivatives / Q000378:metabolism; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D009711:Nucleotides / Q000378:metabolism; D010453:Peptide Synthases / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D013379:Substrate Specificity; D014633:Valine / Q000378:metabolism
chemical_list: D002250:Carbon Radioisotopes; D009711:Nucleotides; D010710:Phosphates; D000501:Allylglycine; D015074:2-Aminoadipic Acid; C006507:vinylglycine; D002233:Carbocysteine; D000255:Adenosine Triphosphate; D010453:Peptide Synthases; C095368:alpha-aminoadipyl-cysteinyl-valine synthetase; D014633:Valine; D003545:Cysteine; D005998:Glycine