Open AccessCloning and characterization of a haloarchaeal heat shock protein 70 functionally expressed in Escherichia coli
Author(s) -
Zhang Hao,
Lin Lu,
Zeng Chi,
Shen Ping,
Huang YuPing
Publication year - 2007
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2007.00881.x
Subject(s) - hsp70 , biology , chaperone (clinical) , heat shock protein , escherichia coli , gene , microbiology and biotechnology , recombinant dna , molecular cloning , genetics , complementary dna , medicine , pathology
The Hsp70 molecular chaperone machine is constituted by the 70‐kDa heat shock protein Hsp70 (DnaK), cochaperone protein Hsp40 (DnaJ) and a nucleotide‐exchange factor GrpE. Although it is one of the best‐characterized molecular chaperone machines, little is known about it in archaea. A 5.2‐kb region containing the hsp70 ( dnaK ) gene was cloned from Natrinema sp. J7 strain and sequenced. It contained the Hsp70 chaperone machine gene locus arranged unidirectionally in the order of grpE , hsp70 and hsp40 ( dnaJ ). The hsp70 gene from Natrinema sp. J7 was overexpressed in Escherichia coli BL21 (DE3). The recombinant Hsp70 protein was in a soluble and active form, and its ATPase activity was optimally active in 2.0 M KCl, whereas NaCl had less effect. In vivo , the haloarchaeal hsp70 gene allowed an E. coli dnak ‐null mutant to propagate λ phages and grow at 42°C. The results suggested that haloarchaeal Hsp70 should be beneficial for extreme halophiles survival in low‐salt environments.