title: Cassette mutagenesis of Met121 in azurin from Pseudomonas aeruginosa.
abstract: Cassette mutagenesis was used to exchange the suggested copper ligand Met121 in azurin to all other amino acids, and a stop codon. The mutant proteins were characterized by optical absorption spectroscopy and EPR. At low pH, all mutants exhibit the characteristics of a blue type 1 copper protein, indicating that methionine is not needed to create a blue copper site. At high pH, the Glu121 and the Lys121 mutants constitute a new form of protein-bound copper that is outside the range of type 1 copper.
authors.affiliation: Department of Biochemistry and Biophysics, Chalmers University of Technology, Göteborg, Sweden.
authors.forename: B G
authors.initials: BG
authors.lastname: Karlsson
authors.forename: M
authors.initials: M
authors.lastname: Nordling
authors.forename: T
authors.initials: T
authors.lastname: Pascher
authors.forename: L C
authors.initials: LC
authors.lastname: Tsai
authors.forename: L
authors.initials: L
authors.lastname: Sjölin
authors.forename: L G
authors.initials: LG
authors.lastname: Lundberg
mesh_terms: D001400:Azurin / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D003198:Computer Simulation; D003300:Copper / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D008715:Methionine / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D015345:Oligonucleotide Probes; D011550:Pseudomonas aeruginosa / Q000235:genetics*; D013053:Spectrophotometry
chemical_list: D015345:Oligonucleotide Probes; D001400:Azurin; D003300:Copper; D008715:Methionine