Abstract:
Membrane binding of proteins such as short chain dehydrogenase reductases or tail-anchored proteins relies on their N- and/or C-terminal hydrophobic transmembrane segment. In this review, we propose guidelines to characterize such hydrophobic peptide segments using spectroscopic and biophysical measurements. The secondary structure content of the C-terminal peptides of retinol dehydrogenase 8, RGS9-1 anchor protein, lecithin retinol acyl transferase, and of the N-terminal peptide of retinol dehydrogenase 11 has been deduced by prediction tools from their primary sequence as well as by using infrared or circular dichroism analyses. Depending on the solvent and the solubilization method, significant structural differences were observed, often involving α-helices. The helical structure of these peptides was found to be consistent with their presumed membrane binding. Langmuir monolayers have been used as membrane models to study lipid-peptide interactions. The values of maximum insertion pressure obtained for all peptides using a monolayer of 1,2-dioleoyl-sn-glycero-3-phospho-ethanolamine (DOPE) are larger than the estimated lateral pressure of membranes, thus suggesting that they bind membranes. Polarization modulation infrared reflection absorption spectroscopy has been used to determine the structure and orientation of these peptides in the absence and in the presence of a DOPE monolayer. This lipid induced an increase or a decrease in the organization of the peptide secondary structure. Further measurements are necessary using other lipids to better understand the membrane interactions of these peptides.
摘要:
蛋白质如短链脱氢酶还原酶或尾部锚定蛋白的膜结合依赖于它们的N-和/或C-末端疏水性跨膜区段。在这次审查中,我们提出了使用光谱和生物物理测量来表征此类疏水性肽段的指南。视黄醇脱氢酶8、RGS9-1锚定蛋白C末端肽的二级结构含量,卵磷脂视黄醇酰基转移酶,以及视黄醇脱氢酶11的N末端肽已通过预测工具从其一级序列以及使用红外或圆二色性分析得出。根据溶剂和溶解方法,观察到显著的结构差异,通常涉及α-螺旋。发现这些肽的螺旋结构与其推测的膜结合一致。Langmuir单层已用作膜模型来研究脂质-肽相互作用。使用单层1,2-二油酰基-sn-甘油基-3-磷酸-乙醇胺(DOPE)获得的所有肽的最大插入压力值大于膜的估计横向压力,因此表明它们结合了膜。偏振调制红外反射吸收光谱法已经用于在不存在和存在DOPE单层的情况下确定这些肽的结构和取向。这种脂质诱导肽二级结构的组织增加或减少。需要使用其他脂质进行进一步测量以更好地理解这些肽的膜相互作用。