PRODUCTION, ANALYSIS AND BIOACTIVITY OF RECOMBINANT VASOACTIVE-INTESTINAL-PEPTIDE ANALOGS

Recombinant vasoactive intestinal polypeptide (VIP) analogs were expre ssed in Escherichia coli as a fusion protein containing tandemly repea ted multiple copies of a synthetic VIP gene joined to glutathione S-tr ansferase. The encoded protein contains VIP units separated by a linke r peptide, potentially excisable by a double cleavage with endoproteas e factor Xa and hydroxylamine. Expression of different polyVIP genes, from 1 to 32 units, was detected and the production of a 16 VIP polyme r was performed. MonoVIP analogs appended by 5 or 10 amino acids at th eir C terminus were released by factor Xa from this polymerized produc t. They were then submitted to hydroxylamine cleavage to remove the li nker sequence to finally obtain a recombinant VIP analog devoid of any amino acid extension. The biological activity of the recombinant poly VIP and VIP analogs was tested. Although less efficient than the natur al neuropeptide, some of these components bound to VIP receptor, activ ated adenylate cyclase in human colonic adenocarcinoma cells and displ ayed a relaxation activity on guinea pig tracheal rings.