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标题：Cryo-EM structures of GroEL:ES 2 with RuBisCO visualize molecular contacts of encapsulated substrates in a double-cage chaperonin
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作者：Hyunmin Kim ; Junsun Park ; Seyeon Lim 等
期刊名称：iScience
印刷版ISSN：2589-0042
出版年度：2022
卷号：25
期号：1
页码：1-16
DOI：10.1016/j.isci.2021.103704
语种：English
出版社：Elsevier
摘要：SummaryThe GroEL/GroES chaperonin system assists the folding of many proteins, through conformational transitions driven by ATP hydrolysis. Although structural information about bullet-shaped GroEL:ES1complexes has been extensively reported, the substrate interactions of another functional complex, the football-shaped GroEL:ES2, remain elusive. Here, we report single-particle cryo-EM structures of reconstituted wild-type GroEL:ES2complexes with a chemically denatured substrate, ribulose-1,5-bisphosphate carboxylase oxygenase (RuBisCO). Our structures demonstrate that native-like folded RuBisCO density is captured at the lower part of the GroEL chamber and that GroEL's bulky hydrophobic residues Phe281, Tyr360, and Phe44 contribute to direct contact with RuBisCO density. In addition, our analysis found that GroEL:ES2can be occupied by two substrates simultaneously, one in each chamber. Together, these observations provide insights to the football-shaped GroEL:ES2complex as a functional state to assist the substrate folding with visualization.Graphical abstractDisplay OmittedHighlights•Presenting cryo-EM structures of football-shaped GroEL:ES2 encapsulating RuBisCO•Visualizing direct contacts between the chaperone and an encapsulated substrate•Visualizing native-like folded substrate inside the chaperone chamberBiochemistry; Biological sciences; Structural biology