Interactive Configuration through Force Analysis of GM1 Pentasaccharide-Vibrio cholera Toxin Interaction

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• 作者：Jeong Hyun Seo ; Chang Sup Kim ; Hea Yeon Lee ; Tomoji Kawai ; Hyung Joon Cha
• 刊名：Analytical Chemistry
• 出版年：2011
• 出版时间：August 1, 2011
• 年：2011
• 卷：83
• 期：15
• 页码：6011-6017
• 全文大小：894K
• 年卷期：v.83,no.15(August 1, 2011)
• ISSN：1520-6882

文摘

Understanding of the molecular relationships in carbohydrate鈥損rotein interactions provides useful information on biological processes in living organisms and is also helpful for development of potent biomedical agents. Herein, the interaction unbinding force between GM1 pentasaccharide and Vibrio cholera toxin (ctx) proteins was measured using atomic force microscopy (AFM), which enabled us to determine the interaction of ctx holotoxin (ctxAB) with GM1 and the interactive formation. First, the interaction force measured between A and B subunits (ctxA鈥揷txB) was 184.2 卤 4.5 pN, and the unbinding forces were evaluated to confirm the role of ctxA in ctxAB complex formation and were determined to be 443.7 卤 7.5 and 535.7 卤 25.9 pN for GM1鈥揷txB and GM1鈥揷txAB complexes, respectively. The force difference of 90 pN between GM1鈥揷txB and GM1鈥揷txAB might be due to the formation of the cholera toxin complex. Importantly, from the analogue analyses, we understand how structural and binding positional differences in complex carbohydrates affect the interaction with protein and surmise that the GM1鈥揷txAB complex makes a 鈥渢wo-finger grip鈥?formation through the conformational change of a flexible carbohydrate. In conclusion, using AFM force analysis, we successfully quantified and characterized the interactive configuration of carbohydrate鈥損rotein molecules.