Amphibian cathelicidin fills the evolutionary gap of cathelicidin in vertebrate.
Cathelicidins comprise a family of antimicrobial peptides (AMPs) sharing a highly conserved cathelin domain, and play a central role in the innate defense against infection in most of vertebrates. But so far it has not yet been found in amphibians although a large number of other groups of AMPs have been identified. In the current work, the first amphibian cathelicidin (cathelicidin-AL) has been characterized from the frog skin of Amolops loloensis. Cathelicidin-AL (RRSRRGRGGGRRGGSGGRGGRGGGGRSGAGSSIAGVGSRGGGGGRHYA) is a cationic peptide containing 48 amino acid residues (aa) with 12 basic aa and no acidic aa. The chemical synthesized peptide efficiently killed bacteria and some fungal species including clinically isolated drug-resistance microorganisms. The cDNA encoding cathelicidin-AL precursor was cloned from the skin cDNA library of A. loloensis. As other cathelicidins, the precursor of cathelicidin-AL also contains highly conserved anionic cathelin domain of cysteine proteinase inhibitor followed by the AMP fragment at C-terminus. Phylogenetic analysis revealed that as connecting link, the amphibian cathelicidin predates reptilia but postdates fish cathelicidin. The peptide purification combined with gene cloning results confirms the presence of cathelicidin in amphibians and filled the evolutionary gap of cathelicidin in vertebrate, considering amphibians' special niche as the animals bridging the evolutionary land-water gap.
Biotoxin Units of Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223 Yunnan, China.
Xue
X
Hao
Hailong
H
Yang
Ling
L
Wei
Shilong
S
Yang
Wenjuan
W
Zhu
Dongying
D
Ma
Haining
H
Yu
Ren
R
Lai
D000595:Amino Acid Sequence; D029845:Amphibian Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D001483:Base Sequence; D002470:Cell Survival / Q000187:drug effects; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004912:Erythrocytes / Q000187:drug effects; D019143:Evolution, Molecular; D005260:Female; D015870:Gene Expression; D006461:Hemolysis; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010802:Phylogeny; D011898:Ranidae / Q000235:genetics*; D020539:Sequence Analysis, Protein; D013211:Staphylococcus aureus / Q000187:drug effects / Q000648:ultrastructure; D014714:Vertebrates / Q000235:genetics; D054804:Cathelicidins
D029845:Amphibian Proteins; D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D054804:Cathelicidins