掃描式穿隧電流顯微鏡與蛋白質形貌與結構變異分析

Abstract

本論文利用掃描式穿隧電流顯微鏡（Scanning Tunneling Microscopy，簡稱STM）探討鐵蛋白吸附於高定向裂解石墨（Highly Oriented Pyrolytic Graphite，簡稱HOPG）之表面結構，測量其於氫氧化鈉及鹽酸溶液中變質，逐漸改變結構之影像，藉以建立蛋白質岐化與形貌變異關聯性。結果顯示：鐵蛋白經氫氧化鈉溶液處理後表面形貌會逐漸變異，其寬度增大而高度降低，並且顯現塌陷現象。我們也對鹽酸的影響進行探討，發現經由鹽酸處理，鐵蛋白也顯現類似變化，但結構不會呈現塌陷。根據這些結果，我們認為STM具有作為研究蛋白質結構變異之分析方法。

In this thesis, we use scanning tunneling microscopy (STM) to investigate structural changes of proteins during denauration. Ferritin (FT) is a global protein, responsible for iron regulation in biosystems. Because of its spherical structure, we use it as a model protein to monitor any changes in surface structure as adsorbed on HOPG when exposed to basic and acidic reagents, such as 1 M NaOH and 1 M HCl. Experimental results show that in NaOH, the surface morphology of FT changes gradually with immersion time, in which the height decreases from 0.430 to 0.345 nm, but the width increases from 15.240 to 19.538 nm. Besides, the center of the FT shows indentation phenomenon, contrasting to the results found in HCl solutions. Accordingly, we consider STM a useful tool for surface analysis of proteins.