title: Thermotolerance and molecular chaperone function of the small heat shock protein HSP20 from hyperthermophilic archaeon, Sulfolobus solfataricus P2.
abstract: Small heat shock proteins are ubiquitous in all three domains (Archaea, Bacteria and Eukarya) and possess molecular chaperone activity by binding to unfolded polypeptides and preventing aggregation of proteins in vitro. The functions of a small heat shock protein (S.so-HSP20) from the hyperthermophilic archaeon, Sulfolobus solfataricus P2 have not been described. In the present study, we used real-time polymerase chain reaction analysis to measure mRNA expression of S.so-HSP20 in S. solfataricus P2 and found that it was induced by temperatures that were substantially lower (60°C) or higher (80°C) than the optimal temperature for S. solfataricus P2 (75°C). The expression of S.so-HSP20 mRNA was also up-regulated by cold shock (4°C). Escherichia coli cells expressing S.so-HSP20 showed greater thermotolerance in response to temperature shock (50°C, 4°C). By assaying enzyme activities, S.so-HSP20 was found to promote the proper folding of thermo-denatured citrate synthase and insulin B chain. These results suggest that S.so-HSP20 promotes thermotolerance and engages in chaperone-like activity during the stress response.
authors.affiliation: College of Life Sciences, Zhejiang University and Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, Hangzhou 310058, China.
authors.forename: Dong-Chol
authors.initials: DC
authors.lastname: Li
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Bo
authors.initials: B
authors.lastname: Lu
authors.forename: Dian-Fu
authors.initials: DF
authors.lastname: Chen
authors.forename: Wei-Jun
authors.initials: WJ
authors.lastname: Yang
mesh_terms: D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism; D050886:HSP20 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D048229:Sulfolobus solfataricus / Q000378:metabolism*; D013696:Temperature; D015854:Up-Regulation
chemical_list: D019843:Archaeal Proteins; D050886:HSP20 Heat-Shock Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins