Functional Difference between N Domain and C Domain of hEGF and hTGF-alpha.
By exchanging the N domain and C domain of hEGF and hTGF-alpha genes by PCR, two chimeras E-TGF(EGF(1-32)-TGF-alpha(34-50))and T-EGF(TGF-alpha(1-33)-EGF(33-53))were constructed. The wild and chimeric molecules were expressed in E.coli under phoA system. The expressed hEGF, hTGF-alpha and two chimeras were purified. The EGF receptor competitive binding affinity of the four molecules was hEGF > hTGF-alpha and E-TGF > T-EGF and the cell proliferation stimulating activity of them was hTGF-alpha and E-TGF > T-EGF > hEGF. The result suggests that the N domain of hEGF and hTGF-alpha may play a major role in receptor binding activity and C domain of them may be responsible for stimulating cell proliferation.
Yuan
Yu
Y
Shanghai Institute of Biochemistry, the Chinese Academy of Sciences, Shanghai 200031, China. zpli@sunm.shcnc.ac.cn Zai-Ping Li
Zhang
Qian
Q
Huang
Pei-Yong
PY
Wang
Yi-Fei
YF
Zhou
Qing-Wei
QW
Gan
Ren-Bao
RB
Li
Zai-Ping
ZP