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Chaperone action of a versatile small heat shock protein from Methanococcoides burtonii , a cold adapted archaeon
Author(s) -
Laksanalamai Pongpan,
Narayan Suchithra,
Luo Haibin,
Robb Frank T.
Publication year - 2008
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.22261
Subject(s) - chaperone (clinical) , lysozyme , biochemistry , protein folding , heat shock protein , enzyme , chemistry , protein aggregation , thermostability , groel , biology , escherichia coli , microbiology and biotechnology , gene , medicine , pathology
The Methanococcoides burtonii small heat shock protein (Mb‐sHsp) is an αB‐crystallin homolog that delivers protein stabilizing and protective functions to model enzymes, presumably reflecting its role as a molecular chaperone in vivo . Although the gene encoding Mb‐ shsp was cloned from a cold‐adapted microorganism, the Mb‐sHsp is an efficient protein chaperone at temperatures far above the optimum growth temperature of M. burtonii . We show that Mb‐sHsp can prevent aggregation in E. coli cell free extracts at 60°C for 4 h and can stabilize bovine liver glutamate dehydrogenase for 3 h at 50°C. Surface plasmon resonance was used to determine the binding affinity of Mb‐sHsp for denatured proteins. Mb‐sHsp bound tightly to denatured lysozyme but not to the native form. When Mb‐Cpn and Mg 2+ ‐ATP were added to the reaction, bound lysozyme was released from Mb‐sHsp establishing that Mb‐Cpn is able to off‐load folding intermediates from Mb‐sHsp. In addition, Mb‐sHsp and Mb‐Cpn also function cooperatively to protect an enzyme substrate. Through characterization of these M. burtonii chaperones, we were able to reconstitute a key heat shock regulated protein folding function of this cold adapted organism in vitro . Proteins 2009. © 2008 Wiley‐Liss, Inc.