at Google ScholarTitle data
Kiefhaber, Thomas ; Quaas, Rainer ; Hahn, Ulrich ; Schmid, Franz X.:
Folding of ribonuclease T1. 2. Kinetic models for the folding and unfolding reactions.
In: Biochemistry.
Vol. 29
(1990)
Issue 12
.
- pp. 3061-3070.
ISSN 1520-4995
DOI: https://doi.org/10.1021/bi00464a024
Abstract in another language
The slow refolding of ribonuclease T1 was investigated by different probes. Structural intermediates with secondary structure are formed early during refolding, as indicated by the rapid regain of a native-like circular dichroism spectrum in the amide region. This extensive structure formation is much faster than the slow steps of refolding, which are limited in rate by the reisomerization of incorrect proline isomers. The transient folding intermediates were also detected by unfolding assays, which make use of the reduced stability of folding intermediates relative to that of the native protein. The results of this and the preceding paper [Kiefhaber et al. (1990) Biochemistry (preceding paper in this issue)] were used to propose kinetic models for the unfolding and refolding of ribonuclease T1. The unfolding mechanism is based on the assumption that, after the structural unfolding step, the slow isomerizations of two X-Pro peptide bonds occur independently of each other in the denatured protein. At equilibrium a small amount of fast-folding species coexists with three slow-folding species: two with one incorrect proline isomer each and another, dominant species with both these prolines in the incorrect isomeric state. In the mechanism for refolding we assume that all slow-folding molecules can rapidly regain most of the secondary and part of the tertiary structure early in folding. Reisomerizations of incorrect proline peptide bonds constitute the slow, rate-limiting steps of refolding. A peculiar feature of the kinetic model for refolding is that the major unfolded species with two incorrect proline isomers can enter two alternative folding pathways, depending on which of the two reisomerizes first. The relative rates of reisomerization of the respective proline peptide bonds at the stage of the rapidly formed intermediate determine the choice of pathway. It is changed in the presence of prolyl isomerase, because this enzyme catalyzes these two isomerizations with different efficiency and consequently leads to a shift from the very slow to the intermediate refolding pathway.
Further data
| Item Type: | Article in a journal |
|---|---|
| Refereed: | Yes |
| Additional notes: | PubMed-ID: 2110824 |
| Institutions of the University: | Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Former Professors > Professor Biochemistry - Univ.-Prof. Dr. Franz Xaver Schmid Faculties Faculties > Faculty of Biology, Chemistry and Earth Sciences Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Professorship Biochemistry Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Former Professors |
| Result of work at the UBT: | Yes |
| DDC Subjects: | 500 Science > 540 Chemistry |
| Date Deposited: | 12 May 2015 08:18 |
| Last Modified: | 20 Apr 2022 12:24 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/13294 |