| Abstrakt: |
Three single chain gonadotropins were designed based on the three-dimensional-structure of human choriogonadotropin and structure/activity relationships of the glycoprotein hormones. In each single chain, the C-terminal end of the human choriogonadotropin β subunit is connected via Ser-Gly repeats to the N-terminal end of the α subunit. In addition, two of the single chains have truncated subunits. The three mutants were expressed in CHO cells. In vitro binding of two of the three mutants to the human lutropin/ choriogonadotropin receptor was found It be comparable to wild-type lutropin. In contrast, both the receptor binding and the in vitro bioactivity of the mutant with truncated α and β subunits in which the β26-110 disulphide bond cannot be formed, are lowered relative to wild-type lutropin. The fact that this mutant still displays biological activity shows that the seat-belt arrangement proposed by Isaacs and coworkers [Lapthorn, A. J., Harris, D. C., Littlejohn, A., Lustbader, J. W., Canfield, R. E., Machin, K. J., Morgan, F. J. & Isaacs, N. W. (1994) Nature 369. 455-461] is important but not essential for receptor binding and biological activity in the context of single chain gonadotropins. Single chains in which Ser-Gly spacers are combined with truncated subunits, provide an attractive approach towards the design and generation of novel, biologically active gonadotropins. [ABSTRACT FROM AUTHOR] |
