Ion cooperativity and the effect of salts on polypeptide structure - a   molecular dynamics study of BBA5 in salt solutions

doi:10.1039/c2fd20065a

CORC > 北京大学 > 化学与分子工程学院

	Ion cooperativity and the effect of salts on polypeptide structure - a molecular dynamics study of BBA5 in salt solutions
	Xie, Wen Jun ; Gao, Yi Qin
刊名	法拉第论坛
	2013
关键词	HOFMEISTER SERIES PROTEIN STABILITY PREFERENTIAL INTERACTIONS AQUEOUS-SOLUTIONS SURFACE-TENSION WATER ANIONS SOLVATION HYDRATION MODEL
DOI	10.1039/c2fd20065a
英文摘要	Using molecular dynamics simulations, we investigated effects of inorganic salts on the structure and dynamics of a short alpha, beta-polypeptide, BBA5. The simulations showed that three model salts, NaI, NaF, and Na2SO3, have very different effects on the structure of the polypeptide. The addition of NaI to the aqueous solution caused denaturation and significantly weakened hydrogen bonds of the polypeptide. Na2SO3 strengthened the hydrophobic interactions and increased hydrogen bonding of the polypeptide. Preferred binding of Na+ to the backbone carbonyl groups of BBA5 occurred in the NaI solution, consistent with the weakened protein backbone hydrogen bonds, whereas Na+ is excluded more from the vicinity of the protein backbone in the Na2SO3 solution. This difference in Na+ binding correlates well with the different propensities of the counter ions approaching the protein surface: SO32- is much more strongly expelled from the protein apolar surface than I-, and demonstrates the importance of cation-anion cooperativity in affecting protein structures. The binding of the two salts to and their effects on the hydration of the protein surface depends strongly on the polarity of the latter. However, both salts reduce the flexibility of the polypeptide and the fluctuation of its hydration layer. These simulations showed that the chaotropic NaI affects protein structure mainly through a direct binding of Na+ to the backbone and I- to the protein surface. The main effect of Na2SO3 manifests in strengthening the hydrophobic interaction and consequently the hydrogen bonding of the protein, more likely through an "indirect" mechanism. In addition, the simulations showed that NaF has a similar effect as Na2SO3 (but weaker than the latter, consistent with their positions in the Hofmeister series).; http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000313815400012&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701 ; Chemistry, Physical; SCI(E); PubMed; 8; ARTICLE; 191-206; 160
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/149788]
专题	化学与分子工程学院
推荐引用方式 GB/T 7714	Xie, Wen Jun,Gao, Yi Qin. Ion cooperativity and the effect of salts on polypeptide structure - a molecular dynamics study of BBA5 in salt solutions[J]. 法拉第论坛,2013.
APA	Xie, Wen Jun,&Gao, Yi Qin.(2013).Ion cooperativity and the effect of salts on polypeptide structure - a molecular dynamics study of BBA5 in salt solutions.法拉第论坛.
MLA	Xie, Wen Jun,et al."Ion cooperativity and the effect of salts on polypeptide structure - a molecular dynamics study of BBA5 in salt solutions".法拉第论坛 (2013).