State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences* Department of Chemistry, Graduate Programs of Biotechnology, Chemistry and Materials Science, University of Alabama in Huntsville**
○Minghuang Chen* Xiaomin Hou* Qi Peng* Feng Yang* Liqing Chen** Mingdong Huang*
Trichosanthin (TCS) is a type 1 Ribosome inactivity protein which was first isolated from the root tuber of Trichosanthe kirilowii Maxim and crystallized by Chinese scientists. TCS has been crystallized from barbital buffer, using NaNO3 as precipitant, the crystals belong to space group C2 with cell parameters a=75.60 Å, b=75.44 Å, c=88.36 Å, β=99.50°. TCS has also been crystallized from citrate buffer with KCl as precipitant, the crystals belong to space group P212121 with cell parameters a=38.305 Å, b=76.225 Å, c=79.213 Å. Crystalline TCS has multiple pharmacological properties including abortifacent, anti-tumor and anti-HIV. When the crystallized TCS was further purified using Mono-S column, two distinct protein peaks were designated as α- and β-TCS according to the reverse order of elution from the Mono-S column, the minor peak was labelled β-TCS, which had an area less than 20% in total. Both α- and β-TCS showed a single band with an apparent molecular weight of 27 kDa by SDS-PAGE. ESI-MS analysis indicated that the molecular weight of β-TCS is 27143 Da， slightly less than that of α-TCS, 27167 Da. Highly purified β-TCS has been crystallized using KCl as precipitant. The crystals belong to space group P212121 with cell parameters a=38.244 Å, b=86.934 Å, and c=135.785 Å, and have two molecules in the asymmetric unit. A data set to 1.6 Å resolution was collected with synchrotron source. We are grateful for financial support from NSFC (No.39970872) and NSF of Fujian Province (C97052).