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Kern, Gunther ; Kern, Dorothee ; Schmid, Franz X. ; Fischer, Gunter:
A kinetic analysis of the folding of human carbonic anhydrase II and its catalysis by cyclophilin.
In: The Journal of Biological Chemistry.
Bd. 270
(1995)
Heft 2
.
- S. 740-745.
ISSN 1083-351X
DOI: https://doi.org/10.1074/jbc.270.2.740
Abstract
The kinetics of unfolding and refolding of human carbonic anhydrase II (HCAII) and its catalysis by the peptidyl-prolyl-cis/trans-isomerase cyclophilin were investigated. HCAII contains 15 trans- and 2 cis-prolyl peptide bonds, and, when long-term denatured, virtually all unfolded molecules contain non-native prolyl isomers. In unfolding these molecules (Us) are produced slowly in a biphasic process reflecting the isomerization of several trans-prolines and of one cis-proline. In refolding, the rapid formation of an intermediate of the molten globule type is followed by several slow prolyl isomerizations, which determine the rate of reactivation. By a short 10-s incubation in 5.0 M guanidinium chloride at 2 degrees C, unfolded HCAII species with all prolines still in the native conformation (Uf) could be produced. Surprisingly, only a fraction of Uf refolds rapidly, but the other molecules refold slowly. Evidently, some prolyl peptide bonds isomerize early in refolding, at the stage of the molten globule and as a consequence, molecules with incorrect prolyl isomers are formed in competition with the productive folding of Uf. This fraction of slow-folding molecules is strongly increased when cyclophilin is present, because it accelerates the formation of non-native prolyl isomers as long as the molecules remain in the molten globule state. Later cyclophilin catalyzes the isomerization of these prolyl peptide bonds toward the native state, which are stabilized in their conformation by further folding to the native state. This catalysis is very efficient, because only prolines that are accessible in the molten globule are involved in this sequence of isomerization and reisomerization.
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| Publikationsform: | Artikel in einer Zeitschrift |
|---|---|
| Begutachteter Beitrag: | Ja |
| Zusätzliche Informationen: | PubMed-ID: 7822304 |
| Institutionen der Universität: | Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Ehemalige Professoren > Professur Biochemie - Univ.-Prof. Dr. Franz Xaver Schmid Fakultäten Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Professur Biochemie Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Ehemalige Professoren |
| Titel an der UBT entstanden: | Ja |
| Themengebiete aus DDC: | 500 Naturwissenschaften und Mathematik > 540 Chemie |
| Eingestellt am: | 15 Mai 2015 07:35 |
| Letzte Änderung: | 28 Feb 2023 13:22 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/13474 |