Folding studies on ribonuclease A, a model protein.

Ribonuclease A (RNase A), an unusually well defined enzyme, has been a test protein in the study of a wide variety of chemical and physical methods of protein chemistry. These methods have in turn provided many insights into the functional properties of RNase A, as well as topics of general interest in protein biochemistry. The presence of four disulfide bonds and the existence of two cis peptide bonds preceding prolines in the native state have complicated the analysis of the folding pathway of RNase A. In this review, we present some new information about the folding of RNase A obtained recently by quench-flow H/D exchange combined with NMR and single-jump and double-jump stopped-flow techniques.