Aarhus Universitets segl

English

Du er her: AU » Om AU » Organisation » Rate of isomerisation of peptidyl-proline bonds as a prob...

Om AU

Rate of isomerisation of peptidyl-proline bonds as a probe for interactions in the physiological denatured state of chymotrypsin inhibitor 2

Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avis › Tidsskriftartikel › Forskning › peer review

DOI

  • Yee Joo Tan, Cambridge Ctr. for Protein Eng., National University of Singapore
    • ,
  • Mikael Oliveberg, Cambridge Ctr. for Protein Eng., Lund University
    • ,
  • Daniel E. Otzen
  • Alan R. Fersht, Cambridge Ctr. for Protein Eng.

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 has all trans peptidyl-proline bonds, is much faster than that of the slow-folding species, which have one or more cis peptidyl-proline bonds. In CI2, the slow-folding species can be classified into two groups by their rates of refolding, temperature-dependence, pH-dependence and [GdmCl]-dependence of the rate constants and the effect of peptidyl-prolyl isomerase on the rate constants. The replacement of Pro6 by Ala removes one of the slow refolding phases, suggesting that the cis peptidyl-Pro6 conformation is solely responsible for one of the slow-folding species. Pro6 is located in a region of the protein where non-random interactions have been found in a series of N-terminal fragments of CI2 (residues 1 to 13, 1 to 25, 1 to 28 and 1 to 40). In addition, NMR studies on a mutant fragment, (1-40)T3A, have confirmed that this non-native interaction is associated with the bulky side-chain of Trp5. The atypical rate of cis to trans isomerisation of the peptidyl-Pro bond is indicative of the presence of a similar hydrophobic cluster in the physiological denatured state of intact CI2.

OriginalsprogEngelsk
TidsskriftJournal of Molecular Biology
Vol/bind269
Nummer4
Sider (fra-til)611-622
Antal sider12
ISSN0022-2836
DOI
StatusUdgivet - 20 jun. 1997

Se relationer på Aarhus Universitet Citationsformater

ID: 139498003