Asymmetric functional interaction between chaperonin and its plastidic cofactors

• Published in: The FEBS journal 2015-10, Vol.282 (20), p.3959-3970
• Main Authors: Guo, Peng, Jiang, Shan, Bai, Cuicui, Zhang, Wenjuan, Zhao, Qian, Liu, Cuimin
• Format: Article
• Language: English
• Subjects: Algal Proteins - agonists; Algal Proteins - chemistry; Algal Proteins - genetics; Algal Proteins - metabolism; Arabidopsis; Arabidopsis - metabolism; Arabidopsis Proteins - agonists; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Bacterial Proteins - agonists; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; chaperonin; Chaperonin 10 - agonists; Chaperonin 10 - chemistry; Chaperonin 10 - genetics; Chaperonin 10 - metabolism; Chaperonin 60 - agonists; Chaperonin 60 - chemistry; Chaperonin 60 - genetics; Chaperonin 60 - metabolism; chaperonins; Chlamydomonas; Chlamydomonas - metabolism; Chloroplasts; Chloroplasts - metabolism; Cpn60; Enzymes; Escherichia coli; Escherichia coli - metabolism; Escherichia coli Proteins - agonists; Escherichia coli Proteins - chemistry; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; folding; GroEL; Group I Chaperonins - agonists; Group I Chaperonins - chemistry; Group I Chaperonins - genetics; Group I Chaperonins - metabolism; Microbiology; Models, Molecular; Molecular Weight; Protein Multimerization; Protein Refolding; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - metabolism; Recombinant Proteins - chemistry; Recombinant Proteins - metabolism; Rhodospirillum rubrum; Rhodospirillum rubrum - enzymology; Rhodospirillum rubrum - metabolism; ribulose-bisphosphate carboxylase; Ribulose-Bisphosphate Carboxylase - chemistry; Ribulose-Bisphosphate Carboxylase - genetics; Ribulose-Bisphosphate Carboxylase - metabolism; Rubisco
• ISSN: 1742-464X; 1742-4658
• DOI: 10.1111/febs.13390

The specific cochaperonin, chloroplast chaperonin (Cpn)20, consisting of two tandem GroES‐like domains, is present abundantly in plant and algal chloroplasts, in addition to Cpn10, which is similar in size to GroES. How Cpn20 oligomers, containing six or eight 10‐kDa domains, cooperate with the heptameric ring of chaperonin at the same time as encountering symmetry mismatch is unclear. In the present study, we characterized the functional cooperation of cochaperonins, including two plastidic Cpn20 homo‐oligomers from Arabidopsis (AtCpn20) and Chlamydomonas (CrCPN20), and one algal CrCPNs hetero‐oligomer, consisting of three cochaperonins, CrCPN11, CrCPN20 and CrCPN23, with two chaperonins, Escherichia coli GroEL and Chlamydomonas CrCPN60. AtCpn20 and CrCPNs were functional for assisting both chaperonins in folding model substrates ribulose bisphosphate carboxylase oxygenase from Rhodospirillum rubrum (RrRubisco) in vitro and complementing GroES function in E. coli. CrCPN20 cooperated only with CrCPN60 (and not GroEL) to refold RrRubisco in vitro and showed differential complementation with the two chaperonins in E. coli. Cochaperonin concatamers, consisting of six to eight covalently linked 10‐kDa domains, were functionally similar to their respective native forms. Our results indicate that symmetrical match between chaperonin and cochaperonin is not an absolute requisite for functional cooperation.