A seqüência nxh1 foi isolada a partir de uma biblioteca de cDNA da glândula de veneno da cobra coral Micrurus corallinus. Essa sequência apresenta similaridade estrutural com as toxinas de \"três dígitos\", e principalmente com as α-neurotoxinas, devendo apresentar 4 pontes dissulfeto deduzidas por comparação com outras proteínas desta família. Porém, essa potencial toxina não possui alguns aminoácidos importantes para a interação com o receptor nicotínico de acetilcolina na junção neuromuscular. A potencial toxina NXH1 foi expressa em E. coli de 3 maneiras distintas. Os melhores resultados foram obtidos quando a NXH1 foi expressa em fusão com uma cauda de histidina. Essa construção permitiu uma rápida e eficiente purificação da proteína recombinante. A proteína de fusão foi usada para a produção de um soro específico anti-NXH1. O soro anti-proteína recombinante, assim como o soro do Instituto Butantan, reconheceu a toxina recombinante em Western blot e ELISA. Além disso, o anti-NXH1 reconheceu em Western blot apenas uma banda presente no veneno de M. corallinus, mas não reconheceu os venenos de outras 10 espécies de Micrurus. Experimentos de ligação mostraram que componentes do veneno de M. corallinus ligam-se aos receptores nicotínicos das membranas de músculo de rato. O soro anti-NXH1 não inibiu a ligação do veneno aos receptores, indicando que, ou a NXH1 não é uma α-neurotoxina, ou o antisoro não consegue impedir a ligação da toxina nativa ao receptor, ou que existem outras a-neurotoxinas do veneno que não são bloqueadas pelo soro anti-NXH1. / The nxh1 sequence has been isolated from a cDNA library from the coral snake Micrurus corallinus\' venom gland. The deduced protein is highly similar to known \"three finger\" α-neurotoxins, with four deduced disulfide bridges. However, the predicted protein lacks some important amino acids for the nicotinic acetylcholine receptor interaction. The potencial toxin NXH1 was expressed in E. coli in three different ways. The best results were obtained when the protein was expressed as a His-tagged fusion protein, which allowed rapid and efficient purification of the recombinant toxin. The fusion protein was used to generate a specific antiserum against NXH1. The produced antiserum, as well as the serum from Instituto Butantan, recognized in ELISA and Western blot the recombinant toxin. Besides, the anti-NXH1 serum recognized in Western Blot a single band from the venom of M. corallines but not the venom from other 10 Micrurus species. Binding experiments showed that the components from M. corallines venom bind to nicotinic acetylcholine receptor in rat muscle membranes. The anti-NXH1 serum did not inhibited the binding of the venom to the receptors. It seems that NXH1 is not an α-neurotoxin, or that the antiserum does not inhibit the binding of the native toxin to the receptor, or that the antiserum is not capable to inhibit the action of other α-neurotoxin from the venom.

I report a characterization of several alleles of the myospheroid (mys) gene which encodes the beta-chain of the Drosophils PS integrins. Genetic analysis revealed that the mysˣᴿ, mutation is antimorphic and the mysˣᴺ mutation is hypomorphic. Protein was detected on Western blots from hemizygous mysˣᴿ and mysˣᴺ animals. No integrin beta-subunit was detected in in situ immunofluorescence assays in mysˣᴿ embryos. However, antigen was detected in a small subset of muscle attachment sites in mysˣᴺ embryos. mysˣᴳ and mysˣᴮ alleles behaved, genetically, as null alleles and no protein was detected on Western blots or in immunofluorescence assays. Complementation tests between mysᵗˢ¹, mysᵗˢ³, and the other lethal mys alleles unusual results which suggest that mys may be a transvecting locus.

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, Departamento de Biologia Celular, 2008. / Submitted by Jaqueline Ferreira de Souza (jaquefs.braz@gmail.com) on 2011-04-16T21:45:32Z No. of bitstreams: 1 2008_AdelsonJoelSilva.pdf: 6538658 bytes, checksum: d53ab6d55ab999a7948e18c47fa70a1c (MD5) / Approved for entry into archive by Jaqueline Ferreira de Souza(jaquefs.braz@gmail.com) on 2011-04-16T21:46:58Z (GMT) No. of bitstreams: 1 2008_AdelsonJoelSilva.pdf: 6538658 bytes, checksum: d53ab6d55ab999a7948e18c47fa70a1c (MD5) / Made available in DSpace on 2011-04-16T21:46:58Z (GMT). No. of bitstreams: 1 2008_AdelsonJoelSilva.pdf: 6538658 bytes, checksum: d53ab6d55ab999a7948e18c47fa70a1c (MD5) / "O inibidor de quimotripsina de Schizolobium parahyba (SPCI) pertence à família Kunitz, inibindo especificamente quimotripsina na proporção molar de 1:1 (Ki = 5,85 x 10-8 M). Este trabalho visa analisar as modificações conformacionais resultantes da associação entre o SPCI e a -quimotripsina por meio de métodos espectroscópicos de fluorescência (estacionária e dinâmica), dicroísmo circular e espalhamento de luz dinâmica (ELD); a cristalização do complexo binário SPCI-quimotripsina também foi realizada utilizando o método da matriz esparsa em gota sentada. O SPCI foi purificado pela precipitação com ácido tricloroacético 1,2% seguido por cromatografia de troca catiônica. A purificação do complexo binário foi realizada por cromatografia de exclusão molecular. O espectro da emissão na interação das moléculas apresentou atenuação da intensidade da fluorescência fixa a max = 332. O gráfico de Stern-Volmer apresentou KSV (103 M-1) praticamente constante em diferentes temperaturas, excluindo a hipótese de atenuação estática ou dinâmica. O decaimento de fluorescência do SPCI ( 1 = 0,67 ns e 1 = 0,52; 2 = 4,98 ns e 2 = 0,45) e da -quimotripsina ( 1 = 0,88 ns e 1 = 0,37; 2 = 4,16 ns e 2 = 0,67) foram melhores ajustadas pelo modelo Discreto e Planck para dois tempos de vida baseado no valor mínimo do 2. Os parâmetros obtidos indicam que a -quimotripsina apresenta duas populações distintas de triptofano: enterrada ( 1) e exposta ( 2); o decaimento bi-exponencial encontrado para o SPCI indica subestados conformacionais do triptofano no estado excitado. A interação do inibidor com a quimotripsina foi analisada através da clássica equação de Stern-Volmer. A interação provocou modificações conformacionais nos micro-ambientes dos triptofanos do complexo, aumentando (redução da hidrofobicidade) e atenuando (aumento da hidrofobicidade) o tempo de vida. Essa modificação foi dependente da concentração da enzima. Os cálculos para Kq (1012 M-1s-1) mostraram que a atenuação registrada pela fluorescência estacionária e dinâmica ocorre por ligação molecular. Os experimentos de ELD mostraram que o SPCI apresenta forma monomérica em solução, independente da concentração, pH e temperatura. Portanto, a atenuação do tempo de vida do complexo é devido provavelmente a estados oligoméricos mais complexos (tetrâmero) da enzima. A presença de NaCl 0,2 M reduziram os valores do tempo de vida para ambas as moléculas separadamente, provavelmente pela redução das interações dos triptofanos com os resíduos circunvizinhos. O sal potencializou a atenuação do tempo de vida acima de 20 M da enzima. A análise do papel das ligações dissulfeto na interação também foi realizada. O gráfico de Stern-Volmer mostrou flutuação ao longo da titulação da quimotripsina, sugerindo flexibilidade conformaconal do SPCI nessas condições. A desnaturação térmica do inibidor não foi possível, mostrando que as ligações dissulfeto não são responsáveis pela estabilidade estrutural do inibidor. As reduções dessas ligações promoveram modificações em valores percentuais na estrutura secundária, o que poderá explicar a flexibilidade conformacional registrada na flutuação gráfica de Stern-Volmer. O cristal do complexo binário do SPCI com -quimotripsina difratando a 2,8 Å foi obtido na condição MES/NaOH 100 mM pH 5.5, PEG 6000 20% (w/v), LiCl2 200 mM e sulfobetaína não-detergente 201 (NDSB-201) como aditivo." . _________________________________________________________________________________ ABSTRACT / "The inhibitor of chymotrypsin Schizolobium parahyba (SPCI) belongs to the Kunitz family, specifically inhibit chymotrypsin at molar ratio of 1:1 (Ki = 5.85 x 10-8 M). This paper aims to analyze the conformational changes resulting from the association between the SPCI-chymotrypsin and by means of fluorescence spectroscopic methods (stationary and dynamic), circular dichroism and dynamic light scattering (SLS), the crystallization of binary SPCI-chymotrypsin complex was also performed using the sparse matrix method in sitting drop. The SPCI was purified by precipitation with trichloroacetic acid 1.2% followed by cation exchange chromatography. The purification of the binary complex was performed by size exclusion chromatography. The emission spectrum of the interaction of the molecules showed attenuation of the fluorescence intensity of fixed max = 332. The Stern-Volmer plot showed KSV (103 M-1) almost constant at different temperatures, without the possibility of static or dynamic attenuation. The decay of fluorescence of GSI (1 = 0.67 ns and 1 = 0, 52, 2 = 4.98 ns and 2 = 0.45) and-chymotrypsin (1 = 0.88 ns and a = 0.37, 2 = 4.16 ns and 2 = 0.67) were better adjusted by Discreet and Planck model for two life times based on the minimum value of 2. The parameters obtained indicate that a-chymotrypsin shows two distinct populations of tryptophan: buried (1) exposed and (2), the bi-exponential decay found for the GSI indicates conformational substates in the excited state of tryptophan. The interaction of the inhibitor with chymotrypsin was analyzed by the classical Stern-Volmer equation. conformational changes triggered interaction in micro-environments of the tryptophans in the complex, increasing (reducing hydrophobicity) and damping ( increased hydrophobicity) the lifetime. This modification was dependent on the concentration of the enzyme. Calculations for KQ (1012 M-1s-1) showed that the fluorescence decay recorded for stationary and dynamic molecular link occurs.'s experiments showed ELD SPCI presents the monomeric form in solution, independent of concentration, pH and temperature. Therefore, the attenuation of the lifetime of the complex is probably due to more complex oligomeric state (tetramer) of the enzyme. The presence of 0.2 M NaCl reduced values ​​of lifetime for both molecules separately, probably by reducing the interactions of tryptophans with the surrounding residues. Salt enhanced the attenuation of lifetime above 20 M of the enzyme. The analysis of the role of disulfide bonds in the interaction also was performed. The Stern-Volmer plot showed fluctuation along the titration of chymotrypsin, suggesting flexibility conformaconal of SPCI under these conditions. The thermal denaturation of the inhibitor was not possible, showing that the disulfide bonds are not responsible for the structural stability of the inhibitor. The reductions of these links have promoted changes in percentages of the secondary structure, which may explain the conformational flexibility in the fluctuation recorded graphic Stern-Volmer. The crystal of the binary complex with SPCI-chymotrypsin diffracting to 2.8 Å was obtained on condition MES / 100 mM NaOH pH 5.5, 20% PEG 6000 (w / v), 200 mM LiCl2 sulfobetaína non-detergent and 201 (NDSB-201) as an additive. "

<p>The Wnt signaling pathway plays a vital role in a multitude of cellular processes across a breadth of multicellular organisms, from simple nematode roundworms such as the Caenorhabditis species to humans. Through the study of this evolutionarily conserved signal transduction pathway in a simple model organism, a greater understanding of the regulation and function of the Wnt pathway can be gained. Emerging research is highlighting the promiscuous nature of Wnt signaling within the network of signaling pathways involved in C. elegans development and aging processes. However, impeding the study of the diverse roles of Wnt signaling in the nematode is the fact that little is known about regulation of key Wnt pathway components in the nematode species, and only a handful of downstream Wnt pathway target genes have been identified. We have used parallel genetic and genomic approaches to elucidate transcriptional targets of the Wnt pathway in C. elegans and the related species C. briggsae. This analysis has uncovered an array of putative Wnt pathway gene targets including pry-1/Axin, a key regulatory component of the pathway. Furthermore, our genome-wide search for Wnt targets has revealed a novel interaction between the Wnt and Hedgehog signaling pathways that is conserved between these two nematode species.</p> / Master of Science (MSc)

<p>Walker 256 cells (W256 cells) were shown to generate oxygen-derived free radicals when activated with the chemotactic peptide N-formyl-L-Methionyl-L-Leucyl-L-Phenylalanine (fMLP). fMLP-stimulated W256 cells, suspended to a concentration of 5x10⁶ cells/ml, produced luminol chemiluminescence equivalent to that generated by 6.5x10^-3 units/ml xanthine oxidase. We also examined human platelets for their ability to generate reactive oxygen species since these are often found at sites of tumour cell arrest in vivo. While others had inferred that human platelets generate reactive oxygen species, we have obtained direct morphological evidence confirming that this can occur. Preliminary studies showed that in the presence of the reactive oxygen species-generating system xanthine-xanthine oxidase, the release of ³H-2-deoxyglucose from prelabeled endothelial cell monolayers was a sensitive index of endothelial cell perturbation. Since the previous experiments suggested that tumour cell contact with the endothelium was required in order to observe isotope release, we asked if the release of ³H-2-deoxyglucose was dependent upon the adhesion of W256 cells to the endothelium. We suggest that W256 cell adhesion to endothelial cell monolayers is partially regulated by vitronectin receptor expression and that endothelial cell perturbation by reactive oxygen species is dependent on tumour cell adhesion. We have also obtained evidence suggesting that W256 cells degrade subendothelial cell matrices by a process involving both the generation of hydrogen peroxide and the secretion of a metalloproteinase. We suggest that the W256 cells can secrete a latent metalloproteinase of molecular weight 94 kD which may be activated, with a loss in molecular weight, by hydrogen peroxide or APMA. In summary, we provide evidence which supports the novel concept that some tumour cells may mediate vessel wall injury by generating reactive oxygen species and suggest that this may promote the metastasis of these cells in vivo. Such a hypothesis has not been postulated previously. (Abstract shortened by UMI.)</p> / Doctor of Philosophy (PhD)

This thesis reports the efforts towards the design and synthesis of a small molecule walker that would potentially move along the track directionally by exploiting the secondary interactions between the track and the walker. This thesis also reports the synthesis and operation of a light driven molecular shuttle featuring a novel acylpyridyl hydrazone station. Chapter One describes the biological walkers which are the source of inspiration towards the synthetic walkers, characteristics of a walker, previously described small molecule walkers and recent progress on the synthesis of molecular shuttles that operate under variety of different stimuli. Chapter Two describes the design and synthetic efforts towards a molecular walker that has the potential to operate directionally along the track by exploiting secondary interactions between the walker and the track namely the hydrogen bonding interactions introduced by subtle incorporation of excellent hydrogen bond donor/acceptor squaramides. This chapter briefly mentions the hydrogen bonding capabilities of squaramides on which the directional operation relies. Optimization of critical reactions and attempted strategies for the assembly of the whole machine is described as well. Chapter Three describes the synthesis and operation of 1- and 2- station [2]-rotaxanes that operate under light irradiation. 2- station [2]-rotaxane that function as a light driven molecular shuttle presents remarkable positional fidelity with high efficacy. The bistable acyl pyridyl station is incorporated as a photo active station upon which light irradiation alters the binding affinities towards the macrocycle. Series of rotaxanes featuring different amide based stations were synthesized to determine the best non-photo active station.

Made available in DSpace on 2014-06-11T19:30:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-05-14Bitstream added on 2014-06-13T19:19:37Z : No. of bitstreams: 1 tosqui_p_dr_sjrp.pdf: 1146910 bytes, checksum: 6aba6f1c199f0bebfaeca2737005759b (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A influência de ânions sobre as características estruturais e funcionais de hemoglobinas (Hb) vem sendo alvo de pesquisas de nosso laboratório nos últimos anos. Estudos anteriores mostraram que a ligação preferencial de ânions como o Cl- e fosfatos orgânicos (2,3-DPG, IHP) entre outros à desoxi-Hb humana (HbA), modula o equilíbrio entre dois estados alostéricos desoxigenados possíveis, estados To e Tx, livre e complexado com ânions, respectivamente. Medidas funcionais utilizando o método de estresse osmótico, que determina o número de moléculas de água que se liga a superfície da Hb, acompanhando a oxigenação, mostraram que o estado To é um estado com hidratação e afinidade ao oxigênio intermediárias ao Tx e ao oxi-R. Assim, a oxigenação da Hb demanda um modelo considerando estes três estados, To, Tx e R, modulados pela presença de ânions em solução. O íon cloreto é um dos ânions de maior importância fisiológica. A presença de sítios específicos para sua ligação, bem como seu sistema de ligação para a Hb, contudo, são controversos. Evidências estruturais e funcionais apontaram os resíduos arginina 141 e 92 da cadeia alfa como possíveis sítios de ligação de cloreto à Hb. Para investigar essa hipótese, realizamos estudos funcionais variando atividade de água e pH (efeito Bohr), em função da presença de cloreto com hemoglobinas mutantes para essas posições. As hemoglobinas selecionadas foram Chesapeake (R92L), J-Cape Town (R92Q), desArg (141Δ) e Chesapeake desArg (R92L,141Δ). Aspectos estruturais dessas Hbs foram obtidos através de espectroscopia 1H RMN. Todas as Hbs estudadas apresentaram afinidade maior ao oxigênio quando comparadas à HbA, para todas as condições experimentais. Estudos de variação da atividade de água em função da concentração de cloreto mostraram que a única... / The influence of anions on structural and functional properties of hemoglobins (Hb) has been studied by our research group for the last few years. Former studies have shown that the preferential binding of anions, such as Cl and organic phosphates (2,3-DPG, IHP) among others to human deoxy-Hb (HbA), modulates the equilibrium between two possible deoxy states: To and Tx, free and complexed with anions respectively. Functional measurements using the osmotic stress method, which allows the determination of the number of water molecules that binds to the protein surface upon the change in protein conformation induced by oxygenation, showed that To state has intrinsic affinity and hydration intermediate of those of Tx and oxy-R . Hence, Hb oxygenation requires a three state model, considering To, Tx and R, modulated by the presence of anions in solution. Chloride is one of the most important physiological ions and the presence of specific binding sites of this anions is controversial. Structural and functional evidence have pointed to Arginines 141 and 92 as possible binding sites for chloride to Hb. To investigate this hypothesis, we have performed functional studies, changing the water activity and pH (Bohr effect), in function of chloride concentration with recombinants Hbs for these positions. The selected hemoglobins are Chesapeake (R92L), J-Cape Town (R92Q), desArg (141Δ) eandChesapeake desArg (R92L,141Δ). Structural features were obtained through 1H NMR spectroscopy. All Hbs studied have higher affinity than HbA for all experimental conditions. Water activity studies in function of chloride concentration showed that the only Hb that can be adjusted with the three state model is Hb desArg, whereas the other Hbs don’t present the Tx state, fact confirmed by the number of water molecules bound to each... (Complete abstract click electronic access below)

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.

Made available in DSpace on 2014-06-11T19:22:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-08-24Bitstream added on 2014-06-13T18:49:56Z : No. of bitstreams: 1 costa_lc_me_sjrp_parcial.pdf: 205173 bytes, checksum: bf8330ba8ebec2e33d2e94ec3f85ca8c (MD5) Bitstreams deleted on 2015-06-25T13:01:07Z: costa_lc_me_sjrp_parcial.pdf,. Added 1 bitstream(s) on 2015-06-25T13:03:25Z : No. of bitstreams: 1 000624262_20151231.pdf: 180856 bytes, checksum: 0c0db07749af7e17dd04bbdebcc70b88 (MD5) Bitstreams deleted on 2016-01-04T10:26:22Z: 000624262_20151231.pdf,. Added 1 bitstream(s) on 2016-01-04T10:28:15Z : No. of bitstreams: 1 000624262.pdf: 814952 bytes, checksum: c2e88a5f2759a15bbe1e835ebd0266af (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Mastoparanos são uma família de peptídeos líticos, extraídos do saco de veneno de vespas sociais, que apresentam moderada a intensa atividade antimicrobiana e alguns são hemolíticos e citotóxicos. Embora o mecanismo de ação destes peptídeos não seja bem compreendido ainda, aceita-se que envolva desestabilização da fase lipídica da membrana celular. Acredita-se que a carga líquida do peptídeo e sua hidrofobicidade média contribuam na modulação da atividade lítica e na seletividade. Nesta dissertação apresentamos um estudo de quatro peptídeos mastoparanos que possuem resíduos ácidos e básicos resultando em uma carga elétrica líquida variando de +1 a +4. Este estudo envolve a análise conformacional destes peptídeos em vesículas zwitteriônicas e aniônicas por dicroísmo circular. Suas atividades líticas foram avaliadas usando espectroscopia de fluorescência monitorando a recuperação da intensidade de fluorescência devido à liberação de marcador fluorescente encapsulado em vesículas. As constantes de partição destes peptídeos em vesículas zwitteriônicas foram também determinadas por espectroscopia de fluorescência usando um método de análise que é independente de modelo. Com o objetivo de entender a influência de resíduos ácidos e a carga líquida dos peptídeos e sua hidrofobicidade na interação peptídeo-lipídio, foram estimadas as contribuições energéticas eletrostáticas e não eletrostática. Para alcançar este objetivo, os resultados obtidos nas isotermas de ligação por fluorescência foram associados com medidas de potencial zeta. Foi observado que a afinidade destes peptídeos em vesículas zwitteriônicas decresce com a carga líquida do peptídeo e as curvas de dose-resposta são mais cooperativas para os dois peptídeos com as cargas mais baixas. Os peptídeos com maior carga apresentaram uma maior afinidade... / Mastoparans are a family of lytic peptides extracted from the venom sac of wasps which present moderate to intense antimicrobial activity and some of them are hemolytic and cytotoxic. Although the mechanism of action of these peptides are still not completely understood, it is accepted that it involves the destabilization of the lipidic phase of the cell membrane. It is believed that both the peptide net electrical charge and its mean hydrophobicity contribute to modulate their lytic activity and selectivity. In this dissertation we present a study of four mastoparan peptides which have acidic and basic residues resulting in net electrical charges ranging from +1 to +4. This study involves the conformational analysis of these peptides in zwitterionic and anionic lipid vesicles by circular dichroism. Their lytic activities were evaluated using fluorescence spectroscopy by the release of fluorescent dye entrapped in these two types of vesicles. The partition constants of these peptides to zwitterionic vesicles were also determined by fluorescence spectroscopy using a method of analysis which is model independent. Aiming to understand the influence of acidic residues and of the peptides net charge and hydrophobocity on the peptide-lipid interaction, the electrostatic and non electrostatic energetic contributions were estimated. To achieve this goal it was used the association of the results of fluorescence binding isotherms and zeta potential measurements. It was observed that the affinity and lytic activity of these peptides in zwitterionic vesicles decrease with the peptides net electrical charges and the dose-response curves are more cooperative for the two peptides with lower net charges. The more charged peptides exhibit higher affinity and lytic activity in anionic vesicles. The most charged peptide displayed the higher selectivity for the vesicles studied. The present work... (Complete abstract click electronic access below)

Orientador: José Roberto Ruggiero / Coorientador: Jorge Chahine / Banca: Manoel de Arcísio Miranda Filho / Banca: Pedro Pascutti / Banca: Ronaldo Junio de Oliveira / Banca: Alexandre Sumán de Araújo / Resumo: A anandamida é uma molécula anfipática que tem papel fundamental nas funções neurofisiológicas, sendo o agonista endógeno dos receptores canabinóides conhecidos como CB1 e CB2, os mesmos receptores dos compostos psicoativos da Cannabis sativa. Estudos mostram que a anandamida é capaz de realizar suas funções neurofisiológicas mesmo com seus receptores inativos, sugerindo uma atuação independente de receptores. Essa hipótese aliada com a teoria dos lipídios sugere que a anandamida interaja com os fosfolipídios alterando suas propriedades elásticas que levam a uma abertura ou fechamento das proteínas de membrana que são responsáveis por seu efeito biológico. As propriedades elásticas de uma bicamada lipídica podem ser associadas com seu perfil de pressão lateral, dessa forma, para obtermos informações a respeito do modo de ação independente de receptor investigamos como a anandamida particiona em uma bicamada de DOPC e quais propriedades estruturais e elásticas são alteradas por ela. Os resultados mostraram que a preferência do AEA é particionar na bicamada com seus grupos hidrofílicos voltados para a fase aquosa, na posição próxima ao grupo fosfato e éster e mantendo uma estrutura preferencial estendida, onde sua cauda acílica fica protegida das moléculas de água no núcleo hidrofóbico da bicamada. A crescente concentração de AEA não é capaz de alterar significantemente propriedades da membrana como, espessura, área por lipídio e parâmetro de ordem, porém altera... / Abstract: Anandamide is an amphipathic molecule that plays a fundamental role in neurophysiological functions, being the endogenous agonist of the cannabinoid receptors known as CB1 and CB2, the same receptors of the psychoactive compounds of Cannabis sativa. Studies show that anandamide is able to perform its neurophysiological functions even with its inactive receptors, suggesting an independent performance of receptors. This hypothesis allied with the lipid theory suggests that anandamide interacts with the phospholipids by altering its elastic properties that lead to an opening or closing of the membrane proteins that are responsible for its biological effect. The elastic properties of a lipid bilayer can be associated with its lateral pressure profile, so, to obtain information about the receptor-independent mode of action, we investigated how anandamide partitions in a DOPC bilayer and which structural and elastic properties are altered for her. The results showed that the AEA preference is to partition the bilayer with its hydrophilic groups facing the aqueous phase, in the position close to the phosphate and ester group and maintaining an extended preferred structure, where its acrylic tail is protected from the water molecules in the hydrophobic core of the bilayer. The increasing concentration of AEA is not capable of significantly changing membrane properties such as thickness, area by lipid and order parameter, but it significantly alters the lateral pressure profile and ... / Doutor