Proton-mediated dynamics of the alkaline conformational transition of yeast iso-1-cytochrome c.
The kinetics of the alkaline conformational transition of a Lys 73-->His variant of iso-1-cytochrome c have been investigated using pH jump stopped-flow methods to probe the nature of the ionizable "trigger" group for this conformational change. This mutation moves the pK(a) of the ligand replacing Met 80 from about 10.5 to approximately 6.6 and has unmasked two other ionizable groups, besides the ligand replacing Met 80, that modulate the kinetics of this process. The results are discussed in terms of the impact of ionization equilibria on protein folding mechanisms.
Martinez
Robert E
RE
Department of Chemistry and Biochemistry, University of Denver, 2190 East Iliff Avenue, Denver, Colorado 80208-2436, USA.
Bowler
Bruce E
BE
D019943:Amino Acid Substitution; D045304:Cytochromes c / Q000737:chemistry* / Q000235:genetics; D006639:Histidine / Q000737:chemistry / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes; D007700:Kinetics; D008239:Lysine / Q000737:chemistry* / Q000235:genetics*; D008715:Methionine / Q000737:chemistry / Q000235:genetics; D011487:Protein Conformation; D011522:Protons; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics; D013053:Spectrophotometry / Q000379:methods
C014059:CYC1 protein, S cerevisiae; D007527:Isoenzymes; D011522:Protons; D029701:Saccharomyces cerevisiae Proteins; D006639:Histidine; D045304:Cytochromes c; D008715:Methionine; D008239:Lysine