【摘要】 用浸泡法得到了天花粉蛋白（ＴＣＳ）与ＦＭＰ复合物的晶体，在ＳＩＭＥＮＮＳＸ－２００Ｂ面探测器系统上收集了一套２．０分辨率的Ｘ射线衍射数据。用同晶差值傅立叶法解析了复合物的结构，经Ｘ—ＰＬＯＲ程序修正得到了ＴＣＳ—ＦＭＰ复合物的分子结构并找出了１９７个水分子，最后的Ｒ因子为０．１７２，键长和键角的ＲＭＳ偏差分别为０．０１５和２．９２２度。ＴＣＳ—ＦＭＰ复合物中，ＦＭＰ与天花粉蛋白分子有较好的结合，其结合位置正处于根据三维结构和突变体信息推测的Ｎ一糖苷酶活性口袋之中。它的类嘌呤环夹在Ｙ７０和Ｙ１１１两个侧链环之间，与Ｙ７０环近乎平行，其Ｎ７和Ｎ６分别与ＴＣＳ分子的Ｇ１０９４羰基氧和Ｉ７１的Ｎ成氢键，Ｎ３靠近Ｒ１６３的侧链，其磷酸根则伸向活性口袋的底部，与Ｅ１８９、Ｅ１６０和Ｒ１６３等残基作用。更多还原

【Abstract】 Trichosanthin (TCS) is representative of a large family of Ribosome Inactivating Proteins (RIPs). It is a N-glycosidase that catalytically hydrolyze the adenine ring from a specific adenosine of rRNA. In recent years it was discovered thta TCS is an anti-Human Immunodeficiency Virus (HIV) agent. The structures of P212121 and C2 form were determined at 1.73 and 2.7 respectively. Here we present our crystal stucture of TCS-FMP complex. obtained by soaking native TCS crystals in artificial mother liquor containing 20mg/ml FMP for 48 hours. Data were collected to 2.01 for the complex of TCS-FMP using a SIEMENS X-200B area detector system. Different Fourier method was applied to the structure determination of this complex and X-PLOR package was employed to its refinement. The structure of TCS-FMP was refined to R Factor of 0. 172 with RMS deviations of bond length 0.015 and bond angle 2.922. FMP binds to proteins at the proposed active region with its susceptible adenine ring stacking betWeen Y70 and Y111, and the phosphate group extends to the other end of the region. It forms at least six hydrogen bonds with TCS molecule.更多还原