serrulatus, considered a bona fide novel type of K+ channel neurotoxin. The new toxin, named Ts15 and classified as alpha-KTx 21.1, blocked Kv1.2, Kv1.3, Kv1.6 and Shaker IR in a nanomolar range while it does not block the other KV isoforms tested (Kv1.1, Kv1.4, Kv1.5, Kv2.1, Kv3.1, Kv4.2, Kv4.3 and hERG). We are grateful to Prof. O. Pongs for providing cDNAs for rKv1.2, Kvr1.4, Kvr1.5 and Kvr1.6 channels.

The hKv1.3 clone was kindly provided by Prof. M. L. Garcia, Shaker IR by Prof. G. Yellen, and the hERG clone by Prof. M. Keating. The rKv2.1, hKv3.1, rKv4.2 and rKv4.3 clones were kindly provided by Prof. D.J. Snyders.; G. Mandel (Stony Brook University, Stony Brook, USA) for sharing the rNav1.4 clone; R. G. Kallen (University learn more of Pennsylvania, Philadelphia, USA) for sharing hNav1.5; A.L.Goldin this website (University of California, Irvine, USA) for sharing mNav1.6; J. N. Wood (University College, London,

UK) for sharing rNav1.8; S. H. Heinemann (Friedrich-Schiller-Universität, Jena, Germany) for sharing rβ1; M. S. Williamson (IACR Rothamsted, Harpenden, UK) for sharing DmNaV1 and tipE. This work was supported by grants G.0330.06 and G.0257.08(F.W.O. Vlaanderen), UA P6/31(Interuniversity Attraction Poles Program, Belgian State, Belgian Science Policy), Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). “
“Bothrops snake venoms are a complex mixture of biological active peptides and proteins (Kini and Evans, 1990 and Rosing and Tans, 1992), which can cause local and systemic lesions including eltoprazine pain, edema, hemorrhage, tissue necrosis, and blood coagulation disorders (Barraviera, 1994, Fonseca, 2001, Melo et al., 2005 and Markland, 1998). Snake venom

metalloproteinases (SVMPs) are members of the super family of zinc-dependent proteinases (Jia and Pérez, 2010, Oliveira et al., 2010 and Markland, 1998) and are associated with hemorrhagic and fibrinolytic activities of the venoms (Lou et al., 2005). Based on their cDNA and structural domains SVMPs are classified into four major groups: PI to PIV Bjarnason and Fox (2004). Members of class PI (20–30 kDa) contain only the zinc-dependent proteolytic domain. Class PII members (30–50 kDa) contain both proteolytic and disintegrin domains. The disintegrin domain presents RGD (Arg-Gly-Asp) or KGD (Lys-Gly-Asp) sequences characteristic of disintegrins, responsible for binding with integrins. Free disintegrins can be found in the snake venom as 5–10 kDa hydrolysis products of class PII members. Class PIII members (50–65 kDa) are comprised of three domains, the proteolytic, the disintegrin-like and the cysteine rich domains. In contrast to PII disintegrins, free disintegrin-like domains are not found in the snake venom.