1999年3月
Chloroplast Cpn20 forms a tetrameric structure in Arabidopsis thaliana
Plant Journal
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- 巻
- 17
- 号
- 5
- 開始ページ
- 467
- 終了ページ
- 477
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1046/j.1365-313X.1999.00388.x
Chloroplast chaperonin 20 (Cpn20) in higher plants is a functional homologue of the Escherichia coli GroES, which is a critical regulator of chaperonin-mediated protein folding. The cDNA for a Cpn20 homologue of Arabidopsis thaliana was isolated. It was 958 bp long, encoding a protein of 253 amino acids. The protein was composed of an N-terminal chloroplast transit peptide, and the predicted mature region comprised two distinct GroES domains that showed 42% amino acid identity to each other. The isolated cDNA was constitutively expressed in transgenic tobacco. Immunogold labelling showed that Cpn20 is accumulated in chloroplasts of transgenic tobacco. A Northern blot analysis revealed that mRNA for the chloroplast Cpn20 is abundant in leaves and is increased by heat treatment. To examine the oligomeric structure of Cpn20, a histidine-tagged construct lacking the transit peptide was expressed in E. coli and purified by affinity chromatography. Gel-filtration and cross-linking analyses showed that the expressed products formed a tetramer. The expressed products could substitute for GroES to assist the refolding of citrate synthase under non-permissive conditions. The analysis on the subunit stoichiometry of the GroEL-Cpn20 complex also revealed that the functional complex is composed of a GroEL tetradecamer and a Cpn20 tetramer.
- リンク情報
- ID情報
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- DOI : 10.1046/j.1365-313X.1999.00388.x
- ISSN : 0960-7412
- PubMed ID : 10205903
- SCOPUS ID : 0033103962