title: Distinct features of protein folding by the GroEL system from a psychrophilic bacterium, Colwellia psychrerythraea 34H.
abstract: We investigated the protein folding mechanism of the GroEL system of a psychrophilic bacterium, Colwellia psychrerythraea 34H. The amount of mRNA of the groESL operon of C. psychrerythraea was increased about 6-fold after a temperature upshift from 8 to 18 °C for 30 min, suggesting that this temperature causes heat stress in this bacterium. A σ(32)-type promoter was found upstream of the groESL, suggesting that the C. psychrerythraea groESL is regulated by the σ(32) system, like the groESL in E. coli. The maximum ATPase and CTPase activities of CpGroEL were observed at 45 and 35 °C, respectively, which are much higher than the growth temperatures of C. psychrerythraea. We found that the refolding activity of the CpGroEL system in the presence of ATP is lower than that in the presence of CTP. This suggests that ATP is not the optimum energy source of the CpGroEL system. Analyses for the interaction of CpGroEL-CpGroES revealed that CTP could weaken this interaction, resulting in effective refolding function of the CpGroEL system. From these findings, we consider that the CpGroEL system possesses an energy-saving mechanism for avoiding excess consumption of ATP to ensure growth in a low-temperature environment.
authors.affiliation: Cell-Free Science and Technology Research Center, Ehime University, 3 Bunkyo-cho, Matsuyama, 790-8577, Japan. yamauchi@ccr.ehime-u.ac.jp
authors.forename: Seiji
authors.initials: S
authors.lastname: Yamauchi
authors.forename: Yuya
authors.initials: Y
authors.lastname: Ueda
authors.forename: Mika
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Umihiko
authors.initials: U
authors.lastname: Inoue
authors.forename: Hidenori
authors.initials: H
authors.lastname: Hayashi
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D034241:Alteromonadaceae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018835:Chaperonin 10 / Q000235:genetics / Q000378:metabolism; D018834:Chaperonin 60 / Q000235:genetics / Q000378:metabolism*; D003570:Cytidine Triphosphate / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism; D008291:Malate Dehydrogenase / Q000737:chemistry; D009876:Operon; D011401:Promoter Regions, Genetic; D011489:Protein Denaturation; D017510:Protein Folding; D012333:RNA, Messenger / Q000096:biosynthesis; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry; D013696:Temperature; D014158:Transcription, Genetic; D000520:alpha-Glucosidases / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D018835:Chaperonin 10; D018834:Chaperonin 60; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D003570:Cytidine Triphosphate; D000255:Adenosine Triphosphate; D008291:Malate Dehydrogenase; D000520:alpha-Glucosidases