Crystal structure of group II chaperonin in the open state

AUTHORS

Huo YYanwu , Hu ZZhongjun , Zhang KKai , Wang LLi , Zhai YYujia , Zhou QQiangjun , Lander GGabe , Zhu JJiang , He YYongzhi , Pang XXiaoyun , Xu WWei , Bartlam MMark , Dong ZZhiyang , Sun FFei . Structure (London, England : 1993). 2010 10 13; 18(10). 1270-9

PMID: 20947016[PubMed].
PMCID: PMC3048791.

ABSTRACT

Thermosomes are group II chaperonins responsible for protein refolding in an ATP-dependent manner. Little is known regarding the conformational changes of thermosomes during their functional cycle due to a lack of high-resolution structure in the open state. Here, we report the first complete crystal structure of thermosome (rATcpnβ) in the open state from Acidianus tengchongensis. There is a ∼30° rotation of the apical and lid domains compared with the previous closed structure. Besides, the structure reveals a conspicuous hydrophobic patch in the lid domain, and residues locating in this patch are conserved across species. Both the closed and open forms of rATcpnβ were also reconstructed by electron microscopy (EM). Structural fitting revealed the detailed conformational change from the open to the closed state. Structural comparison as well as protease K digestion indicated only ATP binding without hydrolysis does not induce chamber closure of thermosome.

Tags: 2010