Functional Difference
between N Domain and C Domain of hEGF and hTGF-α
YUAN Yu, ZHANG Qian, HUANG Pei-Yong, WANG Yi-Fei,ZHOU
Qing-Wei, GAN Ren-Bao and LI Zai-Ping
( Shanghai Institute of Biochemistry, the Chinese Academy of Sciences,
Shanghai 200031, China；
1School of Sciences, Shanghai University, Shanghai 201800, China
)
Abstract By exchanging the N domain and
C domain of hEGF and hTGF-α genes by PCR, two chimeras E-TGF(EGF1―32-TGF-α34―50)and
T-EGF(TGF-α1―33-EGF33―53)were constructed. The wild and
chimeric molecules were expressed in E.coli under phoA
system. The expressed hEGF, hTGF-α and two chimeras were purified. The EGF
receptor competitive binding affinity of the four molecules was hEGF >
hTGF-α and E-TGF > T-EGF and the cell proliferation stimulating activity of
them was hTGF-α and E-TGF > T-EGF > hEGF. The result suggests that the N
domain of hEGF and hTGF-α may play a major role in receptor binding activity and
C domain of them may be responsible for stimulating cell proliferation.
Key Words hEGF； hTGF-α； chimera； structure； function
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