PRODUCTION OF AN ATRIAL-NATRIURETIC-PEPTIDE VARIANT THAT IS SPECIFIC FOR TYPE-A RECEPTOR

Receptor-specific variants of atrial natriuretic peptide (ANP) were selected from libraries of filamentous phage particles that displayed single copies of random ANP mutants fused to gene III protein. These ANP variants were differentially selected by binding to immobilized natriuretic peptide receptor A (NPR-A) over competing receptor C (NPR-C) in solution. This method also selected ANP variants with improved secretion expression in Escherichia coli. Several of the identified mutations were combined to produce an efficiently expressed ANP analog that was as potent as wild-type ANP in stimulating NPR-A guanylyl cyclase activity but resistant to inactivation mediated by NPR-C. Such NPR-A-selective analogs should be useful for correlating the various activities of ANP to the relevant receptor and may also be more potent therapeutics in the targeting of NPR-A.