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Mechanism in Conformational Change of Group II Chaperonin
Author(s) -
Yohda Masafumi,
Kanzaki Taro,
Masuda Rie,
Muhamad Sahlan,
Oka Toshihiko
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.850.5
Subject(s) - chaperonin , conformational change , atp hydrolysis , mutant , thermococcus , chemistry , biophysics , biochemistry , atp synthase , crystallography , stereochemistry , protein folding , enzyme , biology , atpase , archaea , gene
Previous studies have shown that ATP drives the conformational change of the group II chaperonin from the open‐lid, substrate binding conformation to the closed‐lid conformation. However, the detailed mechanism of the conformation change is still unknown. To elucidate this issue, we examined the effects of existence of conformational change‐deficient mutant (G65C), ATP hydrolysis‐deficient mutant (D64A/D393A) or helical protrusion‐deleted mutant (Δhelical, Δ245‐276) in the defined ordered fashion on the function of Thermococcus chaperonin complexes. Chaperonin complexes containing G65C or D64A/D393A alternately with wild type exhibit almost same refolding ability with the wild type complex. On the contrary, chaperonin complexes containing Δhelical could not fold denatured proteins. Interestingly, they also exhibited ATP‐dependent conformation change. Their conformation change is likely to be transient because they capture denatured protein even in the presence of ATP whereas addition of ATP impaired the ability of the wild type chaperonin to protect citrate synthase. These results suggest that ATP binding/hydrolysis induces the conformational change to the closed conformation, and its conformation is stabilized by the interaction between helical protrusions.