Our observations suggest that the core residues Met33, Thr40/Asn41 and Gln54 are essential components for the binding of fatty acids by COMPcc. Snake venoms are rich sources of biologically active proteins and polypeptides. Apart from its crucial role in paralyzing and digesting prey, snake venom is also an excellent source for novel toxins. Understanding the mechanisms of action of unique toxins, helps in the discovery of novel receptors and in the development of lead therapeutic molecules. Snake venom toxins can be SAR131675 VEGFR/PDGFR inhibitor broadly categorized as enzymatic and non-enzymatic proteins. They are also classified into various toxin superfamilies. Each superfamily contains structurally similar toxins that exhibit varied pharmacological activities. Some of the well characterized superfamilies of snake venom proteins include three-finger toxins, C-type lectin like proteins, phospholipase A2s, serine proteases and metalloproteases. 3FTxs, nonenzymatic snake venom proteins, are the most abundant toxins found in elapid and colubrid venoms. Besides they have been reported from viperid venoms. 3FTxs are composed of 60–74 amino acid residues and 4–5 disulfide bridges. Structurally, all 3FTxs have a stable fold with three b-stranded loops extending from a central core containing all four conserved disulphide bridges, resembling the three fingers of a hand, and hence their common name. The conserved cysteine residues, along with invariant residues, such as Tyr25 and Phe27, contribute to proper folding. Some 3FTxs have an additional fifth disulfide in loop I and II as in the case of non-conventional toxins and long-chain neurotoxins, respectively. In general, 3FTxs exist as monomers. However, a few of them exist as homo- or heterodimers in which the subunits are held together by either noncovalent interactions or by covalent linkages. For example, k-bungarotoxin and haditoxin exist as noncovalent homodimers where the individual subunits are structurally related to long-chain and short-chain neurotoxins, respectively. The individual subunits are arranged in anti-parallel orientation and are held together mostly by hydrogen bonds between main-chain and side-chain atoms. On the other hand, covalently linked 3FTxs include the homodimeric a-cobratoxin and the heterodimeric irditoxin. The structural analysis of the homodimeric a-CT reveals the presence of a bstrand swap as well as two disulfide linkages between loop I of the individual subunits, thereby stabilizing the entire dimeric structure. In irditoxin, the individual subunits are covalently linked through a single disulfide bond between loop I and loop II. 3FTxs also exhibit minor structural variations in the length and conformation of the loops, and presence of longer C-terminal or N-terminal extensions. Despite overall similar fold, 3FTxs recognize a broad range of distinct molecular targets resulting in diverse biological activities. Based on their biological properties, 3FTxs can be classified as postsynaptic neurotoxins targeting the nicotinic and muscarinic acetylcholine receptors, cardiotoxins/cytotoxins targeting phospholipid membranes, fasciculins targeting acetylcholinesterase, calciseptins and FS2 toxins targeting L-type calcium channels, anticoagulants like naniproin, exactin and siamextin targeting various coagulation complexes, b-blockers like b-cardiotoxin targeting b1- and b2- adrenergic receptors, dendroaspin targeting aIIbb3, cardiotoxin A5 targeting avb3 integrins and antagonists of a1A and a2A adrenergic receptors.