title: Chloroplast cyclophilin is a target protein of thioredoxin. Thiol modulation of the peptidyl-prolyl cis-trans isomerase activity.
abstract: Chloroplast cyclophilin has been identified as a potential candidate of enzymes in chloroplasts that are regulated by thioredoxin (Motohashi, K., Kondoh, A., Stumpp, M. T., and Hisabori, T. (2001) Proc. Natl. Acad. Sci. U. S. A. 98, 11224-11229). In the present study we found that the peptidyl-prolyl cis-trans isomerase activity of cyclophilin is fully inactivated in the oxidized form. Reduction of cyclophilin by thioredoxin-m recovered the isomerase activity. Two crucial disulfide bonds were determined by disulfide-linked peptide mapping. The relevance of these cysteines for isomerase activity was confirmed by the mutagenesis studies. Because four cysteine residues in Arabidopsis thaliana cyclophilin were conserved in the isoforms from several organisms, it appears that this redox regulation must be one of the common regulation systems of cyclophilin.
authors.affiliation: ATP System Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Corporation, and the Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta 4259, Yokohama 226-8503, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Motohashi
authors.forename: Fumie
authors.initials: F
authors.lastname: Koyama
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Nakanishi
authors.forename: Hanayo
authors.initials: H
authors.lastname: Ueoka-Nakanishi
authors.forename: Toru
authors.initials: T
authors.lastname: Hisabori
mesh_terms: D054479:Chloroplast Thioredoxins; D002736:Chloroplasts / Q000201:enzymology / Q000378:metabolism*; D021983:Cyclophilins / Q000378:metabolism*; D010449:Peptide Mapping; D019696:Peptidylprolyl Isomerase / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000378:metabolism*; D013879:Thioredoxins / Q000378:metabolism*
chemical_list: D054479:Chloroplast Thioredoxins; D013438:Sulfhydryl Compounds; D013879:Thioredoxins; D021983:Cyclophilins; D019696:Peptidylprolyl Isomerase