The Rate of Isomerisation of Peptidyl-proline Bonds as a Probe for Interactions in the Physiological Denatured State of Chymotrypsin Inhibitor 2
There are four peptidyl-proline bonds in the 64-residue protein chymotrypsin inhibitor 2 (CI2), all of which are in the trans conformation in the native structure. The isomerisation of one or more of these peptidyl-proline bonds to the cis conformation in the denatured state gives rise to heterogeneity, leading to both fast and slow-folding species. The refolding of the fast-folding species, which