The dramatically increased chaperone activity of small heat-shock   protein IbpB is retained for an extended period of time after the stress   condition is removed

doi:10.1042/BJ20071120

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	The dramatically increased chaperone activity of small heat-shock protein IbpB is retained for an extended period of time after the stress condition is removed
	Jiao, Wangwang ; Hong, Weizhe ; Li, Pulin ; Sun, Shihu ; Ma, Jing ; Qian, Mengding ; Hu, Mengdie ; Chang, Zengyi
刊名	biochemical journal
	2008
关键词	chaperone activity inclusion-body-binding protein B (IbpB) molecular chaperone small heat-shock protein (sHSP) structural flexibility MYCOBACTERIUM-TUBERCULOSIS HSP16.3 ALPHA-A-CRYSTALLIN ESCHERICHIA-COLI SUBUNIT EXCHANGE METHANOCOCCUS-JANNASCHII BINDING HSP26 DISAGGREGATION DISSOCIATION AGGREGATION
DOI	10.1042/BJ20071120
英文摘要	sHSP (small heat-shock protein) IbpB (inclusion-body-binding protein B) from Escherichia coli is known as an ATP-independent holding chaperone which prevents the insolubilization of aggregation-prone proteins by forming stable complexes with them. It was found that the chaperone function of IbpB is greatly modulated by the ambient temperature, i.e. when the temperature increases from normal to heat-shock, the chaperone activity of IbpB is dramatically elevated to a level that allows it to effectively bind the aggregation-prone client proteins. Although it is generally believed that the release and refolding of the client protein from the sHSPs depends on the aid of the ATP-dependent chaperones such as Hsp (heat-shock protein) 70 and Hsp100 when the ambient temperature recovers from heat-shock to normal, the behaviour of the sHSPs during this recovery stage has not yet been investigated. In the present study, we examined the behaviour and properties of IbpB upon temperature decrease from heat-shock to normal. We found that IbpB, which becomes functional only under heat-shock conditions, retains the chaperone activity for an extended period of time after the heat-shock stress condition is removed. A detail comparison demonstrates that such preconditioned IbpB is distinguished from the non-preconditioned IbpB by a remarkable conformational transformation, including a significant increase in the flexibility of the N- and C-terminal regions, as well as enhanced dynamic subunit dissociation/reassociation. Intriguingly, the preconditioned IbpB displayed a dramatic decrease in its surface hydrophobicity, suggesting that the exposure of hydrophobic sites might not be the sole determinant for IbpB to exhibit chaperone activity. We propose that the maintenance of the chaperone activity for such 'holdases' as sHSPs would be important for cells to recover from heat-shock stress.; Biochemistry & Molecular Biology; SCI(E); EI; PubMed; 12; ARTICLE; 1; 63-70; 410
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/345313]
专题	生命科学学院
推荐引用方式 GB/T 7714	Jiao, Wangwang,Hong, Weizhe,Li, Pulin,et al. The dramatically increased chaperone activity of small heat-shock protein IbpB is retained for an extended period of time after the stress condition is removed[J]. biochemical journal,2008.
APA	Jiao, Wangwang.,Hong, Weizhe.,Li, Pulin.,Sun, Shihu.,Ma, Jing.,...&Chang, Zengyi.(2008).The dramatically increased chaperone activity of small heat-shock protein IbpB is retained for an extended period of time after the stress condition is removed.biochemical journal.
MLA	Jiao, Wangwang,et al."The dramatically increased chaperone activity of small heat-shock protein IbpB is retained for an extended period of time after the stress condition is removed".biochemical journal (2008).