摘要
DHDPS是赖氢酸合成通路中第一步的合成酶。将中国春小麦的DHDPS基因质粒移植入RDA8中,得到RDA8/pDB26菌株,本研究通过细胞培养、层析提纯和结晶条件的探索,给出了一个较好的技术路线,并为开展义衍射分析蛋白结构创造了条件,通过该研究,对中国春小麦DHDPS和野种大肠杆菌的DHDPS差异有了一定的了解,并且对细胞培养的MM介质处理,DEAE-Sepharose,Phenyl-Sepharose和MonoQ层析的方法给出具体实验条仲。酶活的检测和蛋白浓度测定都是采取高灵敏度的方法。结晶的SCreening条件对于二种DHDPS有很大的差异。对野种大肠杆茵的DHDPS,需要表面活性剂N-octyl-D-glucopyranoside,pH10.0~10.5,对于中国春小麦一DHDPS则未找到较好的表面活性剂,pH6.8~7.6。中国春小麦一DHDPS晶体培养条件在以往文献中未见报导。
Dihydro dipicolinate synthase (DHDPS)is a first step on the lysine biosynthetic path-way. The plamids of the wild E. coli and Triticum aestivum containing DHDPS gene aresuccessfully expressed in RDA8 and RDA8/pDB26. The programs of purification to bothDHDPS from RDAS and from RDA8/pDB26 are different in few steps. Screening for crys-talline conditions is separatedly considered duing to the obviously thermal stability. The suit-able media for crystallization to both wild DHDPS and wheat DHDPS are in differences withPH, buffer media and salt concentration. We suggest that these differences hint some structurally characteristic behaviors,