Gfral was high expressed in e . coli after iptg induction . by ni2 + chelation affinity chromatography, the purified recombinant gfral protein were obtained . based on the evolutionary trace method, multiple sequence alignment and dendrogram construction were then carried out by the clustalx program and constructed a phylogenetic tree from a multiple sequence alignment for a protein family 2.gdnf的表达及其对pc12基因工程细胞的影响用本教研室已构建好的表达质粒pet一gdnf转化大肠杆菌bl21(de3),经lmmipto诱导gdnf表达,并在niz气nta柱上进行纯化,稀释复性后,纯度达90%以上。