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	小分子热休克蛋白Mj HSP16.5的分级变性; Hierarchical Unfolding of Mj HSP16.5
	王铮 ; 赖兵 ; 曹洁 ; 李竹 ; 瞿丽丽 ; 曹傲能 ; 来鲁华
	2008
关键词	小热休克蛋白 蛋白质折叠 变性剂 分级变性 圆二色谱 Mj HSP16.5 Small heat shock protein Mj HSP16.5 Protein folding Denaturant Hierarchical unfolding Circular dichroism
英文摘要	应用荧光光谱、圆二色光谱、体积排阻色谱、激光动态光散射等技术,研究了来自嗜热古细菌Methanococcus jannaschii(Mj)的小分子热休克蛋白Mj HSP16.5在变性剂作用下的变性过程.研究表明,在pH7时,Mj HSP16.5在8mol·L-1尿素作用下不会发生变性.在pH7条件下,盐酸胍对Mj HSP16.5的变性表现为一个分级过程,分别在2.0、3.0和6.0mol·L-1盐酸胍浓度附近,出现明显的结构变化;到7.0mol·L-1盐酸胍时,Mj HSP16.5才完全变性.降低溶液pH值将使Mj HSP16.5的变性变得更为容易.; Mj HSP16.5 is a small heat shock Protein (sHSP) from the hyperthermophilic methanoarchaeon, Methanococcus jannaschii (Mj), which lives at the environment of high temperature up to 94 degrees C. The structural data showed that Mj HSP16.5 was a 24-mer that formed a hollow sphere with octahedral symmetry. Mj HSP 16.5 was very stable at pH 7 that it maintained the 24-mer structure even at 85 degrees C. In the present study, we investigated the unfolding process of Mj HSP16.5 in the presence of denaturants using several techniques, including circular dichroism (CD), dynamic light scattering (DLS), fluorescence spectroscopy, and size exclusive chromatography (SEC). We found that 8 mol center dot L-1 urea had no obvious effect on the structure of Mj HSPI 6.5 at pH 7. The unfolding of Mj HSP16.5 at pH 7 in the presence of guanidine hydrochloride (GdHC1) showed hierarchical behavior. Three significant transitions were observed around 2.0, 3.0, and 6.0 mol center dot L-1 GdHC1 at pH 7. ANS (8-anilino-1-naphthalenesulfonic acid) titration results showed that the binding ability of Mj HSP16.5 to ANS decreased gradually as the concentration of GdHC1 increased until around 2.0 mol center dot L-1 GdHC1, indicating surface hydrophobic area change, and this first transition was companioned with precipitation of Mj HSP16.5. Acrylamide quenching of fluorescence showed that the Stern-Volmer constant changed at about 3.0 mol center dot L-1 GdHCl, indicating changes of the dimeric interface, and this phase transition was companioned with oligomeric state change from 24-mer to small oligomers (4-mer to 8-mer). The last unfolding phase started around 5.0 mol center dot L-1 GdHCl, with a midpoint of 6.1 mol center dot L-1 GdHCI, and Mj HSP16.5 was completely unfolded at 7.0 mol center dot L-1 GdHCl. We also found that Mj HSP16.5 could be quite easily unfolded at pH 3, where it could be completely unfolded in 4.0 mol center dot L-1 GdHCI.; http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000260347300002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701 ; SCI(E); 中文核心期刊要目总览(PKU); 中国科技核心期刊(ISTIC); 中国科学引文数据库(CSCD); 2; 10; 1745-1750; 24
语种	中文
出处	SCI ; 万方 ; 知网
出版者	物理化学学报
内容类型	其他
源URL	[http://hdl.handle.net/20.500.11897/80021]
专题	化学与分子工程学院
推荐引用方式 GB/T 7714	王铮,赖兵,曹洁,等. 小分子热休克蛋白Mj HSP16.5的分级变性, Hierarchical Unfolding of Mj HSP16.5. 2008-01-01.

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