Replacement of cysteine-107 of Saccharomyces cerevisiae iso-1-cytochrome c with threonine: improved stability of the mutant protein.
Site-directed mutagenesis has been used to change the codon for cysteine-107 of Saccharomyces cerevisiae iso-1-cytochrome c to a threonine codon. The resulting protein is active in vivo, is methylated as in the wild-type protein and has optical properties indistinguishable from those of the wild-type protein. The threonine-107 iso-1-cytochrome c demonstrated fully reversible electrochemical behaviour and a mid-point reduction potential of 272 mV versus NHE. In addition, this mutant does not demonstrate a tendency to autoreduce or to dimerize as does the wild-type protein. These properties of the threonine-107 mutant establish that it will provide a useful background in which to make subsequent mutations for mechanistic and physical studies of yeast iso-1-cytochrome c.
Cutler
R L
RL
Department of Biochemistry, University of British Columbia, Vancouver, Canada.
Pielak
G J
GJ
Mauk
A G
AG
Smith
M
M
D000595:Amino Acid Sequence; D003574:Cytochrome c Group / Q000235:genetics*; D045304:Cytochromes c; D004563:Electrochemistry; D008969:Molecular Sequence Data; D009154:Mutation; D015202:Protein Engineering; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins
C014059:CYC1 protein, S cerevisiae; D003574:Cytochrome c Group; D029701:Saccharomyces cerevisiae Proteins; D045304:Cytochromes c