Research Article

Ranakinestatin-PPF from the Skin Secretion of the Fukien Gold-Striped Pond Frog, Pelophylax plancyi fukienensis: A Prototype of a Novel Class of Bradykinin Receptor Antagonist Peptide from Ranid Frogs

Figure 4

Bioinformatic analysis of the ranakinestatin-PPF biosynthetic precursor with homologs reported from other amphibian sources. Accession numbers for cited sequences are Pelophylax plancyi fukienensis ranakinestatin-PPF (HG518554), Amolops mantzorum antimicrobial peptide mantzorumin-B1 (ADM34242), Odorrana grahami odorranaopin (ADP37000), Odorrana schmackeri ranakinestatin-OS (HG518555), and Bombina maxima skin kininogen-2 (P83055). (a) Comparison of putative N-terminal signal peptide domains of respective biosynthetic precursors. Sites of amino acid differences are indicated with asterisks (6/22). (b) Comparison of acid spacer peptide domains of respective biosynthetic precursors. Sites of amino acid differences are indicated with asterisks (4/20). Note that this domain terminates in the conserved basic amino acid residue doublet (-KR-) (indicated in italics and underlined) that represents the site of propeptide convertase cleavage generating the mature peptide. (c) Comparison of mature (ranakinestatin) peptide domains of respective biosynthetic precursors. Sites of amino acid differences are indicated with asterisks (4/17). (d) The full-length sequence of Bombina maxima skin kininogen-2 indicating domains containing (1) the fully conserved ranakinestatin residues 1–9, (2) the bradykinin receptor agonist peptide, maximakinin (syn. bombinakinin M), and (3) the bradykinin B2-receptor antagonist peptide, kinestatin.
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