... for the stability of HT c-552, and the corresponding regions in the wild-type PA c-551 and itsquintuple mutant. The mutated residues in the quintuple mutant, and the corresponding ones of the ... noncovalentinteractions. We further found that the increase in the stability of the quintuple mutant is almost the same as the sum of the three individual stabilities [9,29]. Thus, the mutation(s) in each of the three ... to the mechanism underlying proteinstability at the amino-acid level. The molecular mechanismsunderlying protein maturation, folding, and stability in bacterial cytochromes c are beginning...