Ruan Weiming, Lindner Eric, Langosch Dieter
Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, D-85354 Freising-Weihenstephan, Germany.
Protein Sci. 2004 Feb;13(2):555-9. doi: 10.1110/ps.03357404.
An oligo-leucine sequence has previously been shown to function as an artificial transmembrane segment that efficiently self-assembles in membranes and in detergent solution. Here, a novel technique, asparagine-scanning mutagenesis, was applied to probe the interface of the self-assembled oligo-leucine domain. This novel approach identifies interfacial residues whose exchange to asparagine leads to enhanced self-interaction of transmembrane helices by interhelical hydrogen bond formation. As analyzed by the ToxR system in membranes, the interface formed by the oligo-leucine domain is based on a leucine-zipper-like heptad repeat pattern of amino acids. In general, the strongest impacts on self-assembly were seen with asparagines located around the center of the sequence, indicating that interaction is be more efficient here than at the termini of the transmembrane domains.
先前已表明，一段寡聚亮氨酸序列可作为一种人工跨膜片段，能在膜和去污剂溶液中高效自组装。在此，一种新技术，即天冬酰胺扫描诱变，被用于探测自组装寡聚亮氨酸结构域的界面。这种新方法可识别出一些界面残基，将这些残基替换成天冬酰胺会通过螺旋间氢键形成增强跨膜螺旋的自相互作用。通过膜中的ToxR系统分析发现，寡聚亮氨酸结构域形成的界面基于一种类似亮氨酸拉链的七肽重复氨基酸模式。一般来说，序列中心附近的天冬酰胺对自组装的影响最强，这表明此处的相互作用比跨膜结构域末端的相互作用更有效。
