Poster 089 - Partial purification and characterization of a fraction from Lycosa erythrognatha

Poster 89. Congresso da Sociedade Brasileira de Toxinologia, 8., Symposium of the Pan American Section of the International Society on Toxinology, 8., 2004, Angra dos Reis, Brasil. Abstracts... J. Venom. Anim. Toxins incl.Trop. Dis., 2004, 10, 3, p.448.

Partial Purification AndCharacterization Of A Fraction From Lycosa erythrognathaVenom With Antimicrobial And Insecticidal Activities.

^1,2Santos, D.M., ^1,2Nascimento, D.G., ³Richardson, M., ²Bemquerer, M.P., ⁴Diniz, C.G., ⁴Farias, L.M., ⁴Carvalho, M.A.R., ⁵De Maria, M., ^1,2Pimenta, A.M.C., ^1,2De Lima, M.E.

1 Lab.Venenos e Toxinas Animais; 2 Núcleo de Biomoléculas - Depto. Bioquímica e Imunologia, 4 Lab. de Microbiologia Oral e Anaeróbios – Depto. De Microbiologia; 5 Lab. Aracnologia, Depto. Zoologia – ICB – Universidade Federal de Minas Gerais. 3 Centro de Pesquisa Professor Carlos Ribeiro Diniz – FUNED. Belo Horizonte, MG. Brasil.

Wolf spiders, or tarantulas, from Lycosa genus, are very common in urban areas in Southeastern region of Brazil. Their venoms are poorly studied and the knowledge of their components can be a step forward to prospect new molecules with biological activity. In this work, we initiate the biochemical characterization of the Lycosaerythrognatha venom by using liquid chromatography (HPLC), mass spectrometry and automated Edman´s degradation. One of the obtained fractions, named 12C.4, was verified to be constituted by two main molecular compounds, with observed molecular masses of 2831.1 and 2847.1, measured by ES-Q-TOF mass spectrometry. Determination of the primary strucutures of these compounds, however, showed that, in fact, it is a complex fraction, constituted of isobaric isoforms highly homologous, with mutations and post-translational modifications at the C-terminal part of their polypeptide chain. Predicted secondary structures of these sequences show amphipathic a-helix, a typical feature of antimicrobial pore-forming peptides. Antimicrobial assays showed that, in fact, this fraction potently inhibits the growth of pathogenic bacteria at micromolar concentrations. Yet, biological assays with the fraction 12C.4 have demonstrated a high lethality in house fly (Muscadomestica) at nanomolar concentrations. Chemical synthesis of this molecule will be used in order to obtain sufficient material to improve biological and structural studies.