Ranatensin-HL: A Bombesin-Related Tridecapeptide from the Skin Secretion of the Broad-Folded Frog, Hylarana latouchii

Abstract

Bombesin-related peptides are a family of peptides whose prototype was discovered in amphibian skin and which exhibit a wide range of biological activities. Since the initial isolation of bombesin from Bombina bombina skin, diverse forms of bombesin-related peptides have been found in the skins across Anura. In this study, a novel bombesin-related peptide of the ranatensin subfamily, named ranatensin-HL, was structurally-characterised from the skin secretion of the broad-folded frog, Hylarana latouchii, through combination of molecular cloning and mass spectrometric methodologies. It is composed of 13 amino acid residues, pGlu-RAGNQWAIGHFM-NH2, and resembles an N-terminally extended form of Xenopus neuromedin B. Ranatensin-HL and its C-terminal decapeptide (ranatensin-HL-10) were chemically synthesised and subjected to in vitro smooth muscle assays in which they were found to display moderate stimulatory effects on rat urinary bladder and uterus smooth muscles with EC50 values in the range of 1–10 nM. The prepro-ranatensin-HL was highly homological to a bombesin-like peptide from Rana catesbeiana at both nucleotide and amino acid levels, which might provide a clue for the taxonomic classification of ranid frogs in the future.

Pharmacological Effects of Two Novel Bombesin-Like Peptides from the Skin Secretions of Chinese Piebald Odorous Frog (Odorrana schmackeri) and European Edible Frog (Pelophylax kl. esculentus) on Smooth Muscle

“…Meanwhile, bombesin-PE was demonstrated to belong to a typical bombesin subfamily, the ranatensins. The precursor sequence alignment of bombesin-OS and bombesin-PE with homologues from other ranid frogs is shown in Figure 2 b [ 18 , 19 , 20 , 21 , 22 ]. The nucleotide sequence of the cDNA encoding bombesin-PE and bombesin-OS precursors have been made available in the European Molecular Biology Laboratory (EMBL) Nucleotide Sequence Database under the accession codes, MF784811 and MF784812.…”

Identification and Target-Modification of SL-BBI: A Novel Bowman–Birk Type Trypsin Inhibitor from Sylvirana latouchii

“…The active substances in amphibian skin secretions have always occupied an essential position in the field of natural drug discovery. Currently, a variety of bioactive peptides of brevinin, temporin, ranatensin, nigrocin and ranacyclin families have been discovered from broad-folded frog (Sylvirana latouchii) [31][32][33][34] and showed potential medicinal value. Here, we found a novel Bowman-Birk type trypsin inhibitor peptide from this species named SL-BBI, which shared the highly conserved '-CWTP 1 SXXPKPC-' ring with the ranacyclin family.…”

A Hylarana latouchii Skin Secretion-Derived Novel Bombesin-Related Pentadecapeptide (Ranatensin-HLa) Evoke Myotropic Effects on the in vitro Rat Smooth Muscles

“…Besides, as other neuropeptides from amphibian skin, including ranatensin-HL, the N-terminal glutamine of ranatensin-HLa was also converted into pyroglutamine, and it was also C-terminally amidated. Nevertheless, compared with ranatensin-HL which was released peculiarly from a 125-amino acid residue large precursor, the size of ranatensin-HLa precursor (72 amino acid residues) was similar to that of other ranid frogs-derived bombesin-related peptide precursors [33]. Moreover, like most biosynthetic precursors of bombesin-related peptide formerly cloned from Ranidae family, yet unlike ranatensin-HL precursor, the N-terminal of ranatensin-HLa was flanked by a common convertase proteolytic site made up of dibasic amino acids (Arg-Arg) (Figure 4).…”

“…The nucleotide and amino acid sequences of the biosynthetic precursor of ranatensin-HLa were highly homological to those of bombesin-like peptides from Odorrana grahami (odorranain-BLP-4) and Odorrana schmackeri (bombesin-OS) (Figure 5). Additionally, taking the high homology of ranatensin-HL from H. latouchii and another bombesin-related peptide from Lithobates catesbeianus [33] into consideration, we guessed that H. latouchii , Odorrana graham , Odorrana schmackeri and Lithobates catesbeianus were likely to have retained bombesin/ranatensin peptides in their skin secretion, or these peptides might be the outcome of convergent evolution [37].…”

“…Comparison of the nucleotide and amino acid sequences of the biosynthetic precursors of ranatensin-HL [33] and ranatensin-HLa. ( a ) Comparison of the translated amino acid sequences of ranatensin-HL and ranatensin-HLa precursors; ( b ) Nucleotide sequences comparison of ranatensin-HL and ranatensin-HLa precursors.…”