Cobra Taiwan

Common Name(s) Chinese Cobra, Taiwan Cobra... 

Similarity of venoms among different sea snakes and Elapidae can also be detected immunologically. For instance, the antibody for Enhydrina schistosa showed cross reactivity with the venoms of Hydrophis cyanocinctus, Lapemis hardwickii, and Pelamis platurus 12). The sea snake antivenin not only neutralizes the toxicity of various sea snake venoms, but also Naja naja atra (Taiwan cobra) venom 13-16). The reverse is also true namely, some Elapidae antivenins are also effective for neutralizing sea snake venom lethality 17-19). 

Studies on the Status of Arginine Residues in Phospholipase A2 from Naja naja atra (Taiwan cobra) snake... 

PLA2 from Naja naja atra (Taiwan cobra) venom was isolated and purified as previously described (Yang et al, 1981). Phenylglyoxal was purchased from Aldrich Chemical Co., 8-anilinonaphthalene sulfonate (ANS) was obtained from Pierce Chemical Co.. The SynChropak RP-18 column (4.6mm x 25cm) was obtained from Synchrom. All other reagents were of analytical grade. 

Tsai, l.-H., Wu, S. H., and Lo, T. B. (1981). The complete amino acid sequence of the phospholipase A2 from the venom of Naja naja atra (Taiwan cobra). Toxicon 19, 141-152. 

Trifluoroethanol has been used to denature proteins and to stabilize structures in peptides via protonation. Direct interactions of the trifluoroethanol with the peptide chain have been inferred from changes in NMR chemical shift and line width. Site-specific interaction has not yet been demonstrated experimentally in solution [39, 40]. Neutron diffraction studies on a similar protonation of lysozyme by ethanol indicate that trifluoroethanol is likely to bind to the carbonyl oxygen on the main chain of the peptide. It is inferred that such a site-specific interacting nature of trifluoroethanol resulted in the enhancement of intramolecular hydrogen bonding of the amide group in the peptide to minimize its exposure to the alcohol. A structural transition from (3 -sheet to a -helix of the Taiwan cobra poison peptide, which is induced by an interaction of trifluoroethanol, has been reported [41 ]. Details on the effects of trifluoroethanol on peptides and proteins are summarized in Ref. [42]. 

For many who study the chemistry of venoms, the neurotoxins hold particular interest. One example would be the polypeptide toxin cobrotoxin that was isolated from the Formosan cobra and analyzed in 1965 by Chen-Chung Yang, a distingmshed chair professor at Tsing Hua University in Taiwan. The primary structure of this neurotoxin is indicated in Figure 1, along with some components of its secondary structure. There are sixty-two residues in the primary structure and four di-sulfide bonds in the secondary structure. If even one of these di-sulfide bonds is somehow disrupted, the polypeptide is rendered nontoxic. This points to the fact that secondary structure is important even in small polypeptides, not only full-size proteins. 

In our laboratory we first isolated the major lethal protein (termed Cobrotoxin) of non-enzymatic nature from the venom of Taiwan cobra Naja naja atra) in 1964 and subsequently purified and crystallized the protein. The primary structure and the disulfide linkages with various efforts by chemical modification and immunological methods in elucidation of the structure-function relationship of this important venom neurotoxin have since been accomplished. Structure-activity correlations have been drawn from chemical modification carried out on both pre- and post-synaptic neurotoxins. With recent advances in DNA recombination and protein engineering, we feel that the time is now ripe to apply these techniques to the isolation and characterization of the genes encoding these toxins. Detailed structural and site-specific mutational studies on the cDNA clones of neurotoxins of both types may complement our previous chemical modifications of the functional role of some amino acid residues in neurotoxins and lead to insight into the modes of action for these biologically active molecules. 

A CASE STUDY OF CARDIOTOXIN III FROM THE TAIWAN COBRA (Naja naja atm)... 

The Taiwan cobra (Naja naja atm) is a rich source for the cardiotoxins (37). To date six isoforms have been isolated from this source (38). The isoforms are numbered on column chromatographic profiles (39). Of the six isoforms, cardiotoxin III (CTX III) is the major fraction. It constitutes 50 - 60% of the total dry weight of the cardiotoxin isoforms and hence the best characterized (of the toxin isoforms) from this source (Naja naja atm) (40). 

Two dimensional Nuclear Magnetic Resonance (2D NMR) technique is facile and offers an easy handle to tackle problems involving structural elucidation of proteins in solution (55). Recently, we successfully employed this technique to study the solution structure (8,32,56) and protein folding (57) aspects of Cardiotoxin III from the Taiwan cobra. 

In this chapter, only a case study of CTX III from the Taiwan cobra is presented. However, we believe that the lesson learnt herein, are generally applicable to all snake venom cardiotoxins. Though a lot of useful information is now available on CTX III and cardiotox-... 

Yu, C., Bhaskaran, R., and Yang, C.C., 1994, Structures in solution of toxins from Taiwan cobra,Aq/fl naja atra, derived from NMR spectra, J. Toxin. Toxicol. Rev. 13 291-315. 

Bhaskaran, R.,Huang, C.C., Chang, D.K., and Yu, C., 1994, Cardiotoxin III from the Taiwan cobra Naja naja atrd) Determination of structure in solution and comparison with short neurotoxins, J. Mol. Biol. 235, 1291-1301. 

Chien, K.Y, Huang, W.N., Jean, J.H., and Wu, W.G., 1991, Fusion of spingomyelin vesicles induced by proteins from Taiwan cobra (Naja naja atra), J. Biol Chem. 266 3232-3259. 

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