title: Asymmetric functional interaction between chaperonin and its plastidic cofactors.
abstract: 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.
authors.affiliation: State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.|University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.|University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.|University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Cuicui
authors.initials: C
authors.lastname: Bai
authors.affiliation: State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.|University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Cuimin
authors.initials: C
authors.lastname: Liu
mesh_terms: D020418:Algal Proteins / Q000819:agonists / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000819:agonists / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000819:agonists / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018835:Chaperonin 10 / Q000819:agonists / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018834:Chaperonin 60 / Q000819:agonists / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002696:Chlamydomonas / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000819:agonists / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D056384:Group I Chaperonins / Q000819:agonists / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008970:Molecular Weight; D055503:Protein Multimerization; D058849:Protein Refolding; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012247:Rhodospirillum rubrum / Q000201:enzymology / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D020418:Algal Proteins; D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D018835:Chaperonin 10; D018834:Chaperonin 60; C478767:Cpn20 protein, Arabidopsis; D029968:Escherichia coli Proteins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D056384:Group I Chaperonins; D012273:Ribulose-Bisphosphate Carboxylase
keywords: Cpn60; GroEL; Rubisco; chaperonin; folding