A Structure-function Analysis of Human GDNF.

The glial cell line-derived neurotrophic factor(GDNF) plays a very important role in the regeneration of the nervous system. Based on the results of the X-ray structure analysis of rat GDNF, human GDNF gene was modified with deletion and insertion mutagenesis by using PCR methods. The various mutants were all highly expressed in E.coli. The recombinant proteins were purified and their survival-promoting activities were determined by using cultures of the spinal cord neurons of embryonic mouse. The results showed that the "cystine knot motif" was critical for the maintenance of GDNF structure the alpha-helix, finger 1 and finger 2 region were critical for GDNF neurotrophic activity and the N-terminus of human GDNF was not essential for its biological functions.