Proteínas de tintas de moluscos marinhos composição, função e mecanismo de ação

Abstract

In shelled molluscs or those in which it is present as vestigial as cephalopods and gastropods opistobrânquios, the lack of external protection led to the evolution of defense mechanisms dominated by the secretion or incorporation of bioactive chemicals. Proteins synthesized again are good examples of these molecules, were found in paints of various species of sea slugs, particularly the genus Aplysia. Many have already revealed belong to protein families with oxidástica activity of L-amino acids (LAAOs), a group which comprises also bioactive proteins found in snake venoms. The characterization therefore biological activities and biochemical profile of these proteins is very useful for us to understand how to give the defense mechanisms of animals and how widespread they are, in addition to providing subsidies to its application biomedicinal. This study aimed to elucidate the mechanisms of action of P-dactilomelina, antibacterial protein purified from Aplysia ink dactylomela, and comparison of protein composition and antimicrobial activities of paint released by two gastropods, A. dactylomela and Bursatella leachii, and a cephalopod, Octopus sp .. The study revealed that dactilomelina-P is an L-amino acid oxidase capable of oxidizing L-lysine and L-arginine, with a higher affinity for L-arginine, with a Km of 0.22 + - 0.16 mM / L for L -lys and 0.015 + - 0.01 mM / L L-arg. It also demonstrated that its antibacterial activity is measured by this property, with the hydrogen peroxide generated in the oxidation enzimáticca, great aprtipação in bacterial inhibition. The protein behaves in a non-bacteriostatic when supplemented with L-lysine and L-angilina, being in the presence of bactericidal. In addition, the antibacterial activity was shown to be dependent on the concentration of amino acids available for oxidation by the protein. Staphylococcus aureus activity must occur through mechanisms that do not induce damage to cell morphology, since we did not observe any morphological change by atomic force microscopy. The analysis of the three pro paint SDS-PAGE revealed the presence in them all, protein bands of about 60 kDa, and bands of lower molecular weight. For Western blot can observe the existence of immunologic identity between proteins of the three dyes, since polyclonal antibodies produced against P-dactilomelina recognized protein (s) of about 60 kDa in ink B. leachii and approximately 30 kDa in ink Octopus sp. Among the three dyes, only the ink of A. dactylomela showed antibacterial and antifungal activities