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-Structure paper
タイトル | Hetero-oligomeric CPN60 resembles highly symmetric group-I chaperonin structure revealed by Cryo-EM. |
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ジャーナル・号・ページ | Plant J, Vol. 98, Issue 5, Page 798-812, Year 2019 |
掲載日 | 2019年3月18日 |
著者 | Qian Zhao / Xiang Zhang / Frederik Sommer / Na Ta / Ning Wang / Michael Schroda / Yao Cong / Cuimin Liu / |
PubMed 要旨 | The chloroplast chaperonin system is indispensable for the biogenesis of Rubisco, the key enzyme in photosynthesis. Using Chlamydomonas reinhardtii as a model system, we found that in vivo the ...The chloroplast chaperonin system is indispensable for the biogenesis of Rubisco, the key enzyme in photosynthesis. Using Chlamydomonas reinhardtii as a model system, we found that in vivo the chloroplast chaperonin consists of CPN60α, CPN60β1 and CPN60β2 and the co-chaperonin of the three subunits CPN20, CPN11 and CPN23. In Escherichia coli, CPN20 homo-oligomers and all possible other chloroplast co-chaperonin hetero-oligomers are functional, but only that consisting of CPN11/20/23-CPN60αβ1β2 can fully replace GroES/GroEL under stringent stress conditions. Endogenous CPN60 was purified and its stoichiometry was determined to be 6:2:6 for CPN60α:CPN60β1:CPN60β2. The cryo-EM structures of endogenous CPN60αβ1β2/ADP and CPN60αβ1β2/co-chaperonin/ADP were solved at resolutions of 4.06 and 3.82 Å, respectively. In both hetero-oligomeric complexes the chaperonin subunits within each ring are highly symmetric. Through hetero-oligomerization, the chloroplast co-chaperonin CPN11/20/23 forms seven GroES-like domains, which symmetrically interact with CPN60αβ1β2. Our structure also reveals an uneven distribution of roof-forming domains in the dome-shaped CPN11/20/23 co-chaperonin and potentially diversified surface properties in the folding cavity of the CPN60αβ1β2 chaperonin that might enable the chloroplast chaperonin system to assist in the folding of specific substrates. |
リンク | Plant J / PubMed:30735603 |
手法 | EM (単粒子) |
解像度 | 3.82 - 4.06 Å |
構造データ | EMDB-6946: EMDB-6947: |
由来 |
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