Kassorins: novel innate immune system peptides from skin secretions of the African hyperoliid frogs, Kassina maculata and Kassina senegalensis.
From defensive skin secretions acquired from two species of African hyperoliid frogs, Kassina maculata and Kassina senegalensis, we have isolated two structurally related, C-terminally amidated tridecapeptides of novel primary structure that exhibit a broad spectrum of biological activity. In reflection of their structural novelty and species of origin, we named the peptides kassorin M (FLEGLLNTVTGLLamide; 1387.8 Da) and kassorin S (FLGGILNTITGLLamide; 1329.8 Da), respectively. The primary structure and organisation of the biosynthetic precursors of kassorins M and S were deduced from cloned skin secretion-derived cDNA. Both open-reading frames encoded a single copy of kassorin M and S, respectively, located at the C-terminus. Kassorins display limited structural similarities to vespid chemotactic peptides (7/13 residues), temporin A (5/13 residues), the N-terminus of Lv-ranaspumin, a foam nest surfactant protein of the frog, Leptodactylus vastus, and an N-terminal domain of the equine sweat surfactant protein, latherin. Both peptides elicit histamine release from rat peritoneal mast cells. However, while kassorin S was found to possess antibacterial activity against Staphylococcus aureus, kassorin M was devoid of such activity. In contrast, kassorin M was found to contract the smooth muscle of guinea pig urinary bladder (EC(50) = 4.66 nM) and kassorin S was devoid of this activity. Kassorins thus represent the prototypes of a novel family of peptides from the amphibian innate immune system as occurring in defensive skin secretions.
Molecular Therapeutics Research, School of Pharmacy, Medical Biology Centre, Queen's University, Belfast BT9 7BL, Northern Ireland, UK.
Hang
H
Chen
Lei
L
Wang
Martin
M
Zeller
Martin
M
Hornshaw
Youjia
Y
Wu
Mei
M
Zhou
Jia
J
Li
Xinxing
X
Hang
Jiqun
J
Cai
Tianbao
T
Chen
Chris
C
Shaw
D000349:Africa; D000595:Amino Acid Sequence; D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology; D001001:Anura / Q000276:immunology*; D001483:Base Sequence; D002176:Candida albicans / Q000187:drug effects; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D006168:Guinea Pigs; D007113:Immunity, Innate / Q000276:immunology*; D066298:In Vitro Techniques; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009130:Muscle, Smooth / Q000187:drug effects; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D016415:Sequence Alignment; D012867:Skin / Q000187:drug effects / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000187:drug effects; D001743:Urinary Bladder / Q000187:drug effects
D000890:Anti-Infective Agents; D018076:DNA, Complementary; D010455:Peptides