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Thermodynamics of Mistic protein folding

Mistic 蛋白质折叠的热力学

基本信息

批准号：
46854696
负责人：
Professor Dr. Sandro Keller
金额：
--
依托单位：
Institut für Molekulare Biowissenschaften
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2007
资助国家：
德国
起止时间：
2006-12-31 至 2013-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/46854696?language=en
关键词：
Thermodynamics Mistic protein folding

项目摘要

In vitro unfolding and refolding studies using chemical denaturants have contributed tremendously to our understanding of the folding thermodynamics and kinetics of water-soluble and β-barrel membrane proteins. However, this is not the case for α-helical membrane proteins, which constitute about one third of all proteins and more than half of all drug targets. We have identified the first example of an α-helical membrane protein of known structure that can be unfolded completely and reversibly by a denaturant: Mistic, a 110-residue, four-span membrane protein from Bacillus subtilis, dissociates from detergent micelles or lipid vesicles and assumes an unfolded monomeric state on titration with urea. Using site-directed mutagenesis, multidimensional spectroscopy, and Φ-value analysis, we aim to exploit this unique property to (i) establish a quantitative comparison of membrane-protein stability in different membrane-mimetic systems (micelles, bicelles, and vesicles); (ii) obtain insights at the amino acid level into the ability of this unusual membrane protein to self-insert spontaneously and in a translocon-independent way into lipid bilayers and biological membranes; and (iii) create a monomeric water-soluble Mistic variant that allows a direct comparison of protein folding between membrane-mimetic and aqueous environments.

使用化学变性剂的体外去折叠和重折叠研究极大地促进了我们对水溶性和β-桶膜蛋白折叠热力学和动力学的理解。然而，α-螺旋膜蛋白的情况并非如此，它占所有蛋白质的三分之一，占所有药物靶点的一半以上。我们发现了第一个已知结构的α-螺旋膜蛋白的例子，它可以通过变性剂完全可逆地解折叠：Mistic，一种来自枯草芽孢杆菌的110个残基的四跨度膜蛋白，从洗涤剂胶束或脂质囊泡中解离出来，并在用尿素滴定时呈现解折叠的单体状态。利用定点突变，多维光谱，和Φ值分析，我们的目标是利用这一独特的性质（i）建立一个定量比较膜蛋白的稳定性在不同的膜模拟系统（胶束、双胞和囊泡）;（ii）在氨基酸水平上深入了解这种不寻常的膜蛋白自发地自我插入和在易位中的能力，独立的方式进入脂质双层和生物膜;和（iii）创建一个单体的水溶性Mistic变体，允许直接比较蛋白质折叠之间的膜模拟和水性环境。