Temperature-dependent regulation of Thermus thermophilus DnaK/DnaJ chaperones by DafA protein.
Genes Cells
; 14(12): 1405-13, 2009 Dec.
Article
in En
| MEDLINE
| ID: mdl-19930469
ABSTRACT
DafA, a unique 8-kDa protein found in Thermus thermophilus, assembles the chaperones DnaK and DnaJ to produce a DnaK(3)-DnaJ(3)-DafA(3) complex (KJA complex). Although, it is known that DafA is denatured irreversibly at nonphysiological 89 degrees C and the KJA complex dissociates into fully active DnaK and DnaJ, the function of the KJA complex is not fully understood. In this article, we report that the reversible dissociation of the KJA complex occurs in a temperature-dependent manner even below physiological 75 degrees C and that excess DafA completely inhibits the chaperone activities of the DnaK system. The inhibited activities are not rescued by supplementing DnaK or DnaJ. The results indicate that DafA inhibits the chaperone activities of both DnaK and DnaJ by forming the KJA complex and can act as a thermosensor under both heat stress and optimal growth conditions.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Bacterial Proteins
/
Thermus thermophilus
/
Molecular Chaperones
Language:
En
Journal:
Genes Cells
Journal subject:
BIOLOGIA MOLECULAR
Year:
2009
Type:
Article
Affiliation country:
Japan