Abstract
Snake venom-metalloproteinases (SVMPs) are the primary factors that disturb hemostasis and cause hemorrhage in the venomous snake bitten subjects. Kaouthiagin is a unique SVMP that binds and cleaves von Willebrand factor (vWF) at a specific peptide bond leading to inhibition of platelet aggregation, which enhances the hemorrhage. Kaouthiagin is a low abundant venom component of Thai cobra (Naja kaouthia); thus, most horse-derived antivenins used for cobra bite treatment do not contain adequate anti-kaouthiagin. This study aimed to produce human single-chain antibody variable fragments (HuscFvs) that bind to and interfere with kaouthiagin activity for further clinical use. Kaouthiagin was purified from N. kaouthia-holovenom by a single-step gel-filtration chromatography. The purified venom component was used in phage-biopanning to select the kaouthiagin-bound HuscFv-displayed-phage clones from a HuscFv-phage display library. The selected phages were used to infect Escherichia coli bacteria. Soluble HuscFvs expressed by three phage-transformed-E. coli clones interfered with cobra kaouthiagin binding to human vWF. Computerized simulation indicated that HuscFv of two phage-transformed E. coli clones formed contact interface with kaouthiagin residues at or near catalytic site and effectively inhibited fibrinogenolytic activity of the kaouthiagin. The HuscFvs have therapeutic potential as an adjunct of antivenins in treatment of bleeding caused by venomous snakebites.
Highlights
Recent estimation on worldwide incidence of venomous snakebites was 5.4 million human cases annually, mostly in Asia, Africa, and Latin America; among them 1.8–2.7 million developed clinical manifestations and 81,000 to 138,000 were fatal [1]
Fractions 46–52 were found to contain protein bands of ~50 kDa in SDS-PAGE, which is the molecular size of the venom kaouthiagin (Figure 2A)
snake venom metalloproteinases (SVMPs) are abundant in Viperidae family of venomous snakes, but they are present only in minute amounts in venoms of the Elapidae family, such as, Naja kaouthia and Ophiophagus hannah [4,25]
Summary
Recent estimation on worldwide incidence of venomous snakebites was 5.4 million human cases annually, mostly in Asia, Africa, and Latin America; among them 1.8–2.7 million developed clinical manifestations and 81,000 to 138,000 were fatal [1]. In Thailand in 2015, the snakebite incidence was 7.06 per 100,000 population and cobra-bites contribute the most frequent hospitalized cases [2]. Naja kaouthia (Thai cobra) is the most common venomous snake found in Thailand [3]. A2 [4,6,7], cobra venom factor [4,8], cardiotoxins [4,9], cytotoxin [4], mocarhagin [4], muscarinic toxin-like protein [4], and snake venom metalloproteinases (SVMPs) [4,10]. The P-II molecule contains two domains including M and disintegrin (D) domains; the P-III class is the high molecular mass
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
