Structural and mechanistic characterization of an archaeal-like chaperonin from a thermophilic bacterium

Young Jun An, Sara E. Rowland, Jung Hyun Na, Dario Spigolon, Seung Kon Hong, Yeo Joon Yoon, Jung Hyun Lee, Frank T. Robb, Sun Shin Cha

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

The chaperonins (CPNs) are megadalton sized hollow complexes with two cavities that open and close to encapsulate non-native proteins. CPNs are assigned to two sequence-related groups that have distinct allosteric mechanisms. In Group I CPNs a detachable co-chaperone, GroES, closes the chambers whereas in Group II a built-in lid closes the chambers. Group I CPNs have a bacterial ancestry, whereas Group II CPNs are archaeal in origin. Here we describe open and closed crystal structures representing a new phylogenetic branch of CPNs. These Group III CPNs are divergent in sequence and structure from extant CPNs, but are closed by a built-in lid like Group II CPNs. A nucleotide-sensing loop, present in both Group I and Group II CPNs, is notably absent. We identified inter-ring pivot joints that articulate during ring closure. These Group III CPNs likely represent a relic from the ancestral CPN that formed distinct bacterial and archaeal branches.

Original languageEnglish
Article number827
JournalNature Communications
Volume8
Issue number1
DOIs
StatePublished - 1 Dec 2017

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