利用拉曼光譜來分析磷脂雙層膜中菌紫質的結構

Abstract

膜蛋白有物質運輸以及敵我生物體辨識的功能，在生物化學、生理學上是非常重要的生物分子。其中，膜蛋白物質運輸的高效率具有被應用在細胞外物質純化的潛力；同時，膜蛋白也被認為是許多疾病致命的關鍵。因此，瞭解膜蛋白在細胞膜中的構型有其必要性。 本篇研究以支撐型磷脂雙層膜出發，建構出膜蛋白能正常發揮功能的原生環境。由於膜蛋白分布在細胞膜內外的胺基酸序列具有不對稱性，細胞膜蛋白在支撐型磷脂雙層膜中的方向性會直接影響到未來的應用。例如，膜蛋白的物質運輸具有方向性，若無法分辨膜蛋白的傳輸方向是輸出或輸往胞內，將會讓製備出來的生物膜將無法正常發揮功能。因此，我們採用能辨別化學鍵種類的拉曼散射光譜作為分析工具，嘗試辨識靠近基材之膜蛋白之胺基酸組成。 本篇研究分成兩個部份。第一部份為使用拉曼光譜分析支撐型磷脂雙層膜的組態，並輔以石墨烯或是金來增強其拉曼散射訊號。第二部份則是以自營性古細菌的一種膜蛋白—菌紫質(bacteriorhodopsin)為例，分析其在支撐型磷脂雙層膜中的方向性。

Lipid membrane proteins has functions of transportation and identification and are important biomolecules on biochemistry and physiology. The high efficiency of transportation function of membrane proteins is potential to apply to purify substances outside a cell. Meanwhile, membrane proteins are also key to cure diseases. As a result, studying on the structure of membrane proteins inside cell membrane is necessary. In this study, we use supported lipid membrane to build a native surrounding for lipid membranes to function normally. Due to the asymmetry of amino acid sequence of membrane proteins across cell membrane, the direction of membrane proteins residing in the supported lipid membrane will affect the future application. For instances, the transportation of some membrane proteins has single direction. If we are unable to figure out the direction, the prepared biomembrane will function normally. Therefore, we use Raman scattering spectroscopy to analyze the amino acid sequence of the membrane protein near the substrate. The first part of this thesis is using Raman spectroscopy to analyze the configuration of supported lipid membrane with the aid of graphene or gold to enhance the Raman scattering signals. The second part is to analyze the direction of the membrane protein in the cell membrane, taking bacteriorhodopsin for example.