Tamamura H, Ikoma R, Niwa M, Funakoshi S, Murakami T, Fujii N
Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
Chem Pharm Bull (Tokyo). 1993 May;41(5):978-80. doi: 10.1248/cpb.41.978.
We investigated the structure-antimicrobial activity relationship of tachyplesin I (T-I). Even when Lys1 and Trp2 were both deleted from the N-terminal end of T-I, the antimicrobial activity against gram-negative bacteria was not decreased. But as Lys1 and Trp2 were deleted one by one, the antimicrobial activity against gram-positive bacteria and antiviral activity were gradually decreased. Deletion of two disulfide bridges caused a significant decrease in all activities. The circular dichroism (CD) spectra revealed that the analogs containing the two disulfide bridges took a beta-sheet structure and that the analogs without the disulfide bridges took a random coil conformation. These results suggest that the beta-sheet structure maintained by two disulfide bridges plays an important role in the antimicrobial activity of T-I.
我们研究了鲎素I（T-I）的结构与抗菌活性的关系。即使从T-I的N末端同时缺失Lys1和Trp2，其对革兰氏阴性菌的抗菌活性也不会降低。但随着Lys1和Trp2逐一缺失，其对革兰氏阳性菌的抗菌活性和抗病毒活性逐渐降低。两个二硫键的缺失导致所有活性显著下降。圆二色性（CD）光谱显示，含有两个二硫键的类似物呈β-折叠结构，而没有二硫键的类似物呈无规卷曲构象。这些结果表明，由两个二硫键维持的β-折叠结构在T-I的抗菌活性中起重要作用。
