Snake Cathelicidin from Bungarus fasciatus Is a Potent Peptide Antibiotics

Abstract

BackgroundCathelicidins are a family of antimicrobial peptides acting as multifunctional effector molecules of innate immunity, which are firstly found in mammalians. Recently, several cathelicidins have also been found from chickens and fishes. No cathelicidins from other non-mammalian vertebrates have been reported.Principal FindingsIn this work, a cathelicidin-like antimicrobial peptide named cathelicidin-BF has been purified from the snake venoms of Bungarus fasciatus and its cDNA sequence was cloned from the cDNA library, which confirm the presence of cathelicidin in reptiles. As other cathelicidins, the precursor of cathelicidin-BF has cathelin-like domain at the N terminus and carry the mature cathelicidin-BF at the C terminus, but it has an atypical acidic fragment insertion between the cathelin-like domain and the C-terminus. The acidic fragment is similar to acidic domains of amphibian antimicrobial precursors. Phylogenetic analysis revealed that the snake cathelicidin had the nearest evolution relationship with platypus cathelicidin. The secondary structure of cathelicidin-BF investigated by CD and NMR spectroscopy in the presence of the helicogenic solvent TFE is an amphipathic α-helical conformation as many other cathelicidins. The antimicrobial activities of cathelicidin BF against forty strains of microorganisms were tested. Cathelicidin-BF efficiently killed bacteria and some fungal species including clinically isolated drug-resistance microorganisms. It was especially active against Gram-negative bacteria. Furthermore, it could exert antimicrobial activity against some saprophytic fungus. No hemolytic and cytotoxic activity was observed at the dose of up to 400 µg/ml. Cathelicidin-BF could exist stably in the mice plasma for at least 2.5 hours.ConclusionDiscovery of snake cathelicidin with atypical structural and functional characterization offers new insights on the evolution of cathelicidins. Potent, broad spectrum, salt-independent antimicrobial activities make cathelicidin-BF an excellent candidate for clinical or agricultural antibiotics.

Understanding the vertebrate immune system: insights from the reptilian perspective

“…In contrast to defensins, most cathelicidins are linear molecules that lack disulfide bridges. A cathelicidin, known as cathelicidin-BF, has been identified in venom from the banded krait Bungarus fasciatus (Wang et al, 2008). Cathelicidin-BF exhibited strong antimicrobial activity against Gram-negative bacteria, some strains of Gram-positive bacteria, including those from the genus Bacillus, as well as activity against several fungi, including C. albicans.…”

“…Cathelicidin-BF exhibited strong antimicrobial activity against Gram-negative bacteria, some strains of Gram-positive bacteria, including those from the genus Bacillus, as well as activity against several fungi, including C. albicans. In many cases, cathelicidin-BF was more potent than ampicillin and benzylpenicillin and was even effective against clinically isolated drug resistant Salmonella typhi and Klebsiella pneumoniae (Wang et al, 2008). A small cationic protein was isolated from the Siamese crocodile (Crocodylus siamensis), which demonstrated antibacterial activity against S. typhi, E. coli, S. aureus, Staphylococcus epidermidis, K. pneumoniae, P. aeruginosa and Vibrio chorelae (Preecharram et al, 2008).…”

Progress in cathelicidins antimicrobial peptides research

“…)。目前, 人、小鼠、兔、羊、 牛、猪、马、驴、鸡、狗、猫和金环蛇等许多物种 中发现的 cathelicidins 均属于 α-螺旋型, 如 LL-37 (Agerberth et al, 1995) 、 BMAP-27 、 CAP-18 、 Pc-CATHs 、Cc-CATHs 、K9CATH、feCath 和 cathelicidin-BF (Wang et al, 2008)等。延伸-螺旋 cathelicidins, 如 indolicidin 和富含 Pro 的抗菌肽类, 因含有特殊的氨基酸组成, 不易形成 α-螺旋构型, 而折叠成了更细长的结构。 包括牛的 Bac4、5、7 和 indolicidin (Scocchi et al, 1998), 来源于山羊的 Bac5, 猪的 prophenin-1、2 和 PR-39 (Pungerčar et al, 1993)等。…”

“…μg/ml、0.6 μg/ml 和 1.2 μg/ml (Wang et al, 2008) (Tamamura et al, 1995;Qu et al, 1996;Yasin et al, 1996;Lehrer & Ganz, 1996) (Shi et al, 1996), 而且 PR-39 诱导 小鼠间质细胞表面硫酸类肝素蛋白多糖 syndecan-1 和 syndecan-4 的表达, 促进组织损伤的修复 (Shi et al, 1996) …”

Salmonella Associated with Snakes (Suborder Serpentes)

“…obs.). Interestingly, snake venom contains biologically active peptides with antimicrobial activity (Lima et al, 2005;Wang et al, 2008).…”