Possible Role of B8Gly
in Insulin Structural Motif
ZHANG Hong, TANG Yue-Hua, FENG You-Min*
( State Key Laboratory of Molecular Biology, Shanghai Institute of
Biochemistry, Shanghai Institutes for Biological Sciences, the Chinese Academy
of Sciences, Shanghai 200031, China )
Abstract In the
insulin structural motif n1-Cys-Gly-X10-Cys-n2-Cys-Cys-X3-Cys-X8-Cys-n3, there
are seven absolutely conserved amino acid residues, and the only Gly is at
position B8. When B8Gly was substituted with Ala by means of site-directed
mutagenesis, a mutant insulin, [B8Ala]human insulin was obtained. The receptor
binding capacity and in vivo biological activity of the [B8Ala]human
insulin were about 2.5% and 10% of native porcine insulin, respectively. The
far-UV circular dichroism (CD) spectra of [B8Ala]human insulin and human
insulin showed that the relative content of α-helix in the mutant somewhat
decreased . The results indicate that the B8Gly in the insulin structural motif
is unreplaceble.
Key words insulin structural motif； insulin mutant； [B8Ala]human insulin
*Corresponding author： Tel, 86-21-64374430-145； Fax, 86-21-64338357； e-mail, [email protected]