A systematic survey of in vivo obligate chaperonin‐dependent substrates |
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Authors: | Kei Fujiwara Yasushi Ishihama Kenji Nakahigashi Tomoyoshi Soga Hideki Taguchi |
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Institution: | 1. Department of Medical Genome Sciences, Graduate School of Frontier Sciences, University of Tokyo, FSB401, Kashiwa, Chiba, Japan;2. Institute for Advanced Biosciences, Keio University, Daihoji, Tsuruoka, Yamagata, Japan;3. PRESTO, Japan Science and Technology Agency, Chiyodaku, Tokyo, Japan |
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Abstract: | Chaperonins are absolutely required for the folding of a subset of proteins in the cell. An earlier proteome‐wide analysis of Escherichia coli chaperonin GroEL/GroES (GroE) interactors predicted obligate chaperonin substrates, which were termed Class III substrates. However, the requirement of chaperonins for in vivo folding has not been fully examined. Here, we comprehensively assessed the chaperonin requirement using a conditional GroE expression strain, and concluded that only ~60% of Class III substrates are bona fide obligate GroE substrates in vivo. The in vivo obligate substrates, combined with the newly identified obligate substrates, were termed Class IV substrates. Class IV substrates are restricted to proteins with molecular weights that could be encapsulated in the chaperonin cavity, are enriched in alanine/glycine residues, and have a strong structural preference for aggregation‐prone folds. Notably, ~70% of the Class IV substrates appear to be metabolic enzymes, supporting a hypothetical role of GroE in enzyme evolution. |
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Keywords: | chaperonin GroEL metabolomics protein folding proteomics |
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