Functional characterization of structural alterations in the sequence of the vasodilatory peptide maxadilan yields a pituitary adenylate cyclase-activating peptide type 1 receptor-specific antagonist.
Maxadilan is a vasodilatory peptide derived from sand flies that is an agonist at the pituitary adenylate cyclase-activating peptide (PACAP) type 1 receptor. Surprisingly, maxadilan does not share significant sequence homology with PACAP. To examine the relationship between structure and activity of maxadilan, several amino acid substitutions and deletions were made in the peptide. These peptides were examined in vitro for binding to crude membranes derived from rabbit brain, a tissue that expresses PACAP type 1 receptors; and induction of cAMP was determined in PC12 cells, a line that expresses these receptors. The peptides were examined in vivo for their ability to induce erythema in rabbit skin. Substitution of the individual cysteines at positions 1 and 5 or deletion of this ring structure had little effect on activity. Substitution of either cysteine at position 14 or 51 eliminated activity. Deletion of the 19 amino acids between positions 24 and 42 resulted in a peptide with binding, but no functional activity. The capacity of this deletion mutant to interact with COS cells transfected with the PACAP type 1 receptor revealed that this peptide was a specific antagonist to the PACAP type 1 receptor.
Moro
O
O
Shiseido Research Center, Yokohama, Kanagawa 223-8553, Japan.
Wakita
K
K
Ohnuma
M
M
Denda
S
S
Lerner
E A
EA
Tajima
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002942:Circular Dichroism; D000242:Cyclic AMP / Q000378:metabolism; D003545:Cysteine / Q000235:genetics / Q000378:metabolism; D017931:DNA Primers; D019476:Insect Proteins / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D016716:PC12 Cells; D011485:Protein Binding; D011487:Protein Conformation; D011817:Rabbits; D051381:Rats; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D011979:Receptors, Pituitary Hormone / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D013056:Spectrophotometry, Ultraviolet; D014665:Vasodilator Agents / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*
D017931:DNA Primers; D019476:Insect Proteins; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D011979:Receptors, Pituitary Hormone; D011994:Recombinant Proteins; D014665:Vasodilator Agents; C069147:maxadilan protein, insect; D000242:Cyclic AMP; D003545:Cysteine