CRYSTAL STRUCTURE OF COMPLEX OF TCS WITH FMP
天花粉蛋白与FMP复合物的晶体结构

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.