Invadolysin (inv) is a member of the M8 class of zinc-metalloproteases and is conserved throughout metazoans. It is essential for development and invadolysin homozygous Drosophila mutants are third instar larval lethal. These larvae exhibit a reduced larval brain size and an absence of imaginal discs. Detailed analysis showed that inv mutants exhibit pleiotropic effects, including defects with chromosome architecture, cell cycle progression, spindle assembly, nuclear envelope dynamics, protein turnover and problems with germ cell migration. These findings indicated that Invadolysin must have a critical role in Drosophila. In order to better understand these roles, I set out to identify genetic interactors of invadolysin. I performed a genetic screen scoring for enhancer/suppressor modification of a ‘rough eye’ phenotype induced by invadolysin overexpression. Screening against the Drosdel ‘deficiency kit’ identified numerous genetic interactors including genes linked to energy regulation, glucose and fatty acid pathways. Immunofluorescence experiments in cultured cells showed that H. sapiens Invadolysin localises to the surface of lipid droplets (LD), and subcellular fractionation confirmed its enrichment to these structures. Lipid droplets are highly dynamic organelles involved not only in energy storage but also in protein sequestration, protein and membrane trafficking, and cell signaling. Drosophila fat bodies are enriched in LDs and therefore important energy stores. In addition, they are nutritional sensors and regulators, which are proposed to be the ortholog of vertebrate liver and adipose tissue. Mutant inv fat bodies appeared smaller and thinner than wild type fat body, and accumulated lower levels of triacylgylcerides. This indicated that the loss of invadolysin might be affecting lipid metabolism and storage, confirming the genetic data. However, it was not clear whether these effects were due to the direct action of Invadolysin. Hence, transgenic fly lines expressing either HA, RFP or FLAG tagged forms of Invadolysin were generated to identify physical interactors of Invadolysin. Subsequent mass spectrometry analysis detected ATP synthase-α, -β and -d as interactors. This result suggested that Invadolysin might play a role in regulating mitochondrial function, which might then be manifest in the fat body as the defects previously observed. Energy levels are known to affect the cell cycle, cell growth, lipid metabolism and inevitably development. Further in vivo and in vitro experiments confirmed this hypothesis. Genetic crosses confirmed the interaction of invadolysin with ATP-synthase subunit-α, whilst staining of mitochondria in mutant third instar larval fat bodies suggested decreased mitochondrial activity. Mutants also showed lower ATP levels and an accumulation of reactive oxygen species, hence indicating the possibility of a dysfunctional electron transport chain. Lipid droplets are known to interact with mitochondria, whilst ATP synthase has been found on lipid droplets by proteomic studies in Drosophila. Therefore, based on these data, we propose that Invadolysin is found, with ATP synthase, on lipid droplets, where Invadolysin (likely acting as a protease) could be aiding the normal processing or assembly of ATP synthase. This interaction is vital for the proper functioning of ATP synthase, and hence mitochondria. In this scenario, cellular ATP needs are not met, energy levels drop which results in an inhibition of fatty acid synthesis, cell and organismal growth defects.

In the context of metalloprotease-mediated transactivation of the epidermal growth factor receptor, different monoclonal antibodies against ADAM17 / TACE were characterized for their ability to block the sheddase. Activity of some of them was observed at doses between 2µg/mL and 10µg/mL. Kinetic analyses showed their activity starting at around 30 minutes. In cellular assays performed with the antibodies, especially upon treatment of cells with sphingosine-1-phosphate a reduction in proliferation was observed with some candidates. Moreover this study provides potential new roles for ß-Arrestins. Their involvement in the triple membrane-passing signal pathway of EGFR transactivation was shown. Furthermore, in overexpressing cellular model systems, an interaction between ADAM17 and ß-Arrestin1 could be observed. Detailed analysis discovered that phosphorylation of ß-Arrestin1 is crucial for this interaction. Additionally, the novel mechanism of UV-induced EGFR transactivation was extended to squamous cell carcinoma. The mechanism happens in a dose dependent manner and requires a metalloprotease to shed the proligand Amphiregulin. The involvement of both ADAM9 and ADAM17, being the metalloproteases responsible for this cleavage, was shown for SCC9 cells. / Im Rahmen dieser Arbeit wurden verschiedene monoklonale Antikörper gegen ADAM17 / TACE im Kontext der Metalloprotease-vermittelten Transaktivierung des Epidermalen Wachstumsfaktors auf ihre Fähigkeit hin untersucht, die Proteaseaktivität zu unterdrücken. Einige von Ihnen zeigten inhibitorische Aktivität bei Konzentrationen zwischen 2µg/ml und 10µg/ml. Die Untersuchung der Zeitabhängigkeit ihrer Wirkungsweise ergab eine Aktivität ab 30 Minuten Vorinkubation. In zellulären Versuchen konnte eine Verminderung der Proliferation besonders nach Stimulation mit Sphingosin-1-Phosphat gezeigt werden. Darüber hinaus konnten möglich neue Funktionen von ß-Arrestinen gezeigt werden. Eine Beteiligung am „triple membrane-passing“ Signalwegs der Transaktivierung des Epidermalen Wachstumsfaktors wurde dargestellt. Zudem wurde eine Interaktion von ß-Arrestin1 und ADAM17 in überexprimierenden Zellsystemen gezeigt. Detaillierte Analysen belegten, dass die Phosphorylierung von ß-Arrestin1 eine notwendige Voraussetzung dafür ist. Weiterhin wurde der neue Mechanismus der UV-vermittelten Aktivierung des epidermalen Wachstumsfaktors auf Plattenephithelkarzinom-Zellen ausgeweitet. Er findet in einer dosisabhängigen Form statt und bedarf einer Metalloprotease zum Aktivieren des Liganden Amphiregulin. Sowohl ADAM9 als auch ADAM17 wurden als die verantwortlichen Metalloproteasen in den untersuchten SCC9 Zellen ermittelt.

Metaloproteases/desintegrinas (MD) isoladas de venenos de serpentes são potentes inibidores de agregação plaquetária e de adesão celular, processos envolvidos em doenças como trombose e câncer. As MD pertencem a classe PIII das SVMPs (´snake venom metalloproteinases´) que são constituídas por três domínios: metaloprotease (M), tipo-desintegrina (D) e rico em cisteína (C). A função dos três domínios nas atividades das moléculas ainda não é totalmente conhecida, e estudos com o objetivo de esclarecer suas funções são importantes para o desenvolvimento de novos fármacos. Algumas proteínas da classe PIII apresentam elevada atividade auto-proteolítica (liberando peptídeo constituído dos domínios D e C) enquanto que em outras PIII esta atividade não é menos evidente. Neste trabalho nós estudamos MD isoladas de veneno de Bothrops jararaca (bothropasina) e Bothrops alternatus (alternagina) em relação aos seus processos de autólise. Alternagina e bothropasina apresentaram diferentes comportamentos em relação à auto-proteólise, apesar do elevado grau de identidade entre as duas moléculas. Nesse trabalho, caracterizamos a estabilidade química e o comportamento de desenovelamento da proteína alternagina nativa pela guanídina HCl usando emissão de fluorescência intrínseca em combinação com espectroscopia de dicroísmo circular ´far´-UV. As amostras de alternagina, purificadas do veneno liofilizado, foram monitoradas por dicroísmo em comprimento de onda de 220nm e os resultados mostraram estruturas intermediárias no processo de desnaturação da proteína. Estudos semelhantes foram feitos com a bothropasina, com o objetivo de relacionar seus diferentes comportamentos auto-proteolíticos com os processos de desnaturação. Nas duas proteínas ocorreu uma alta correlação entre os estudos de auto-proteolise e de desnaturação. As MD isoladas de B. jararaca, jararagina e bothropasina, são isoformas descritas na literatura como isoláveis através de diferentes cromatografias. Neste trabalho, utilizamos os diferentes protocolos descritos para verificar a porção da isoforma majoritária no veneno. As amostras de proteína serão analisadas por espectrometria de massas, uma vez que a região N-terminal das proteínas está bloqueada. / Metalloproteinases/disintegrin (MD) isolated from snake venom are potent inhibitors of platelet aggregation and cell adhesion, processes involved in illnesses as cancer and thrombosis. MD belong to the PIII class of the metalloproteinase/disintegrin gene family and they are constituted by three domains: the catalytic domain, metalloprotease; disintegrin-like (D) and cysteine-rich (R). Some MD proteins are rapidly processed (producing the disintegrin-like/ cysteine-rich domains), while others MD are processed slowly. In this work, we studied the autolysis process of the MD isolated from the venom of Bothrops jararaca (bothropasin) and Bothrops alternatus (alternagin). Despite high sequence identity, alternagin and bothropasin showed different autolysis processes. The processing of the alternagin produces an intermediate with molecular mass of 43kDa whereas in the processing of the bothropasin this intermediate is almost not observable. In this work we studied alternagin and bothropasin under the viewpoint of chemical stability and the unfolding process to guanidine hydrochloride (Gnd-HCl) using dichroism circular and fluorescence spectrometry. The CD spectra (220nm) of the alternagin purified from the lyophilized venom showed an intermediate structure in the unfolding process. These studies were performed on bothropasin with the goal to relate the autolysis and unfolding process. These studies revealed a high correlation between both proteins . The MD isolated from B. jararaca, jararagin and bothropasin, are isophorms purified from different chromatograph processes reported in the literature. In this work, different purification processes were used to check the major isophorm. Due to the blocked N-terminal region, these proteins will be assessed by mass spectrometry.

Os venenos de serpentes são complexas misturas com proteínas e peptídeos que apresentam uma variedade de atividades biológicas. Devido à riqueza de seus componentes, várias moléculas encontradas no veneno vêm sendo utilizadas com fins terapêuticos, como agentes anticoagulantes ou analgésicos. Recentemente, diversos estudos têm mostrado que substâncias oriundas do veneno de serpentes são eficazes agentes antitumorais tanto in vivo quanto in vitro. Os estudos referentes ao veneno de C. vegrandis são escassos, o que o torna um interessante objeto de investigação para o isolamento de possíveis biomoléculas com potencial antitumorigênico. No presente trabalho analisamos este veneno com o intuito de isolar novas toxinas com atividade antitumoral. Observamos atividade em varias frações que apresentaram imunoreatividade frente a um anticorpo anti-jararagina, sugerindo a presença de metaloproteinases que, sabidamente, apresentam atividade contra certos tipos de tumores. Pela análise de seqüenciamento de novo foram identificadas sequencias peptídicas idênticas as encontradas na espécie C.durissus durissus. Foi identificada também uma fração ativa de baixo peso molecular que acreditamos ser um análogo à crotoxina que já foi relatada neste veneno. / Snake venoms are complex mixtures with proteins and peptides that have a variety of biological activities. Due to the high diversity of its components, several molecules found in the venom have been used for therapeutic purposes, such as anticoagulants or analgesics. Recently, several studies have shown that substances derived from snake venom are effective antitumor agents both in vivo and in vitro. The studies on the venom of C. vegrandis are scarce, turning it into an interesting object of investigation for the isolation of new biomolecules with potential antitumour potential. In this paper we analyzed this venom in order to isolate new toxins with antitumor activity. Cytotoxicity was detected in various fractions, and the most active showed immunoreactivity against an anti-jararrhagin, suggesting the presence of metalloproteases. Some toxins from this class have already been shown to be active against certain types of tumors. We also identified a low molecular weight active fraction of believed to be analogous to a crotoxin has already been in this venom.

A DisBa-01, uma desintegrina RGD recombinante ainda não isolada do veneno de Bothrops alternatus, exibe alta afinidade pela integrina aIIbB3, contribuindo para inibição da agregação plaquetária (RAMOS, 2005). DisBa-01 possui também atividades anti-trombótica e anti-metastática comprovadas in vivo (Ramos, 2005). A fim de obter moléculas menores mantendo as atividades da DisBa-01, dois mutantes estão em estudo. Moléculas chamadas DisBa (1-32) e DisBa (1-36) apresentam 32 e 36 resíduos a menos que a DisBa-01, respectivamente, na região N-terminal. Oligonucleotídeos foram construídos e os DNAs foram amplificados por PCR utilizando o plasmídeo pET28a-DisBa-01 como o molde. Os produtos de PCR foram clonados no vetor de expressão pET32a. Análises das seqüências revelaram que os genes e sua fase de leitura estavam completamente corretos. Os plasmídeos recombinantes foram introduzidos em linhagem de E.coli BL21 (DE3). Os plasmídeos recombinantes foram induzidos com IPTG para expressar as proteínas em fusão com a tiorredoxina. As proteínas foram expressas na forma solúvel e com massa molecular coincidente com a previsão. As proteínas de fusão foram purificadas por cromatografia de afinidade em resina de níquel e clivadas com a enzima enteroquinase. As amostras clivadas foram purificadas por cromatografia de filtração a gel. Os passos de purificação e clivagem foram analisados por SDS-PAGE e reação de immunoblotting utilizando o anticorpo anti-Echistatin. Testes de inibição da adesão celular, usando células de melanoma de camundongo B16F10 ricas em integrina avb3, mostraram que a DisBa (1-32) e a DisBa (1-36) são capazes de inibir, aproximadamente, 70% da adesão celular, um resultado semelhante ao encontrado para a molécula de DisBa-01. Portanto, as duas moléculas mutantes da DisBa-01 obtidas apresentaram atividades que podem ser exploradas no desenho de novos medicamentos contra câncer. / DisBa-01, a recombinant RGD-disintegrin still not isolated from B. alternatus venom exhibits high affinity for aIIbB3 integrin, contributing for the inhibition of platelet aggregation (Ramos, 2005). DisBa-01 possesses also antithrombotic and antimetatatic activities in vivo (Ramos, 2005). In order to obtain shorter molecules maintaining activities of DisBa-01 two mutants were studied. Molecules called DisBa (1-32) and DisBa (1-36) have 32 and 36 residues unless DisBa-01, respectively, in the N-terminal region. Oligonucleotides were constructed and the DNAs were amplified by PCR using pET28a-DisBa-01 vector as the template. PCR products were cloned into expression vector pET32a. Sequence analysis showed that reading frames were completely correct. The recombinant plasmids were introduced in BL21(DE3) E.coli strain. The recombinant plasmids were induced with IPTG to express the proteins in fusion with thioredoxin. Proteins were expressed in a soluble form and with molecular mass coincident with prediction. Fusion proteins were purified by affinity chromatography in nickel resin and cleaved with enterokinase enzyme. Samples of cleavage were purified by the gel filtration chromatography. Purification and cleavage steps were analyzed by SDS-PAGE and immunoblotting reaction using anti-Echistatin antibody. Tests inhibition of cell adhesion, using cells from mice B16F10 melanoma rich in integrin avb3, showed that DisBa (1-32) and DisBa (1-36) are able to inhibit approximately 70% of cell adhesion. Therefore the two mutants molecules of the DisBa-01 obtained in this work present activities that can be explored in the design of new medicines against cancer.

A resistência natural do gambá Didelphis marsupialis ao veneno de serpentes se deve a fatores antibiotrópicos presentes em seu soro, do qual DM43 é um dos responsáveis pela inibição da atividade hemorrágica. Com o objetivo de entender melhor o mecanismo de ação desta proteína contra a metaloprotease contida no veneno pretendeu-se, neste trabalho, otimizar as condições de cristalização de DM43, na tentativa de determinar sua estrutura por difração de raios-X. Ensaios de cristalização revelaram que o sulfato de amônio é o precipitante mais eficiente na produção de cristais de DM43. A visualização e indexação dos padrões de difração destes cristais permitiram apenas a determinação dos parâmetros de sua cela unitária, devido a baixa qualidade dos mesmos. Deste modo, os seguintes parâmetros de cela unitária foram encontrados: a = b = 117.34 (0.03) Å, c = 193.39 (0.02)Å, ?=?=90° e ? = 120°, correspondentes ao sistema cristalino trigonal ou hexagonal. A recente determinação da sequência de aminoácidos de DM43, possibilitou modelar sua estrutura tridimensional por homologia utilizando o método de satisfação das restrições espaciais. Os três domínios tipo imunoglobulina de DM43 foram modelados em duas partes a partir da estrutura de referência KIR2DL1(1nkr) homóloga a dois domínios C-terminais de DM43, com apenas 27.72% de identidade. O domínio N-terminal denominado D0, foi modelado separadamente contra o domínio C-terminal de KIR2DL1 com um grau de identidade igual a 28.89%. A partir do programa GRASP e PATCHES, foram detectadas as prováveis regiões de ligação entre as duas partes da molécula e uma possível região responsável pela dimerização no domínio D2 de DM43. Interessantemente, resíduos polares em KIR2DLs que foram substituídos por hidrofóbicos em DM43, concentrando-se em uma face do domínio D2 ausente de sítios de glicosilação, o que coincide com as observações de dimerização do receptor do hormônio de crescimento. Um motivo estrutural característico de receptores hematopoiéticos identificados como WSXWS box, foi encontrado em todos os domínios de DM43, especialmente no domínio D2. Supõe-se que a sua existência esteja relacionada com a orientação relativa dos domínios por manter o primeiro triptofano do motivo posicionado exatamente na interface entre os domínios. Surge ainda uma fita extra (F´), no domínio D2, não pertencente ao enovelamento imunoglobulina devido a presença da Pro273, muito bem conservada, a três resíduos do motivo WSXWS. Esta fita parece desempenhar um papel importante na orientação do motivo pois além de formar ligações de hidrogênio com a fita G do domínio anterior, posiciona corretamente o primeiro triptofano do motivo na interface. Somando-se a isto, a presença de resíduos hidrofóbicos na interface dos domínios D1 e D2pode estar contribuindo para a orientação angular relativa menor que 90° entre os dois domínios. Uma interpretação análoga a de hormônios de crescimento sugere que, os loops entre as fitas AB, CC´ e EF do domínio 1, BC e FG do domínio 2 e o linker entre estes dois domínios, estejam envolvidos na interação da metaloprotease com DM43. / The natural resistance of the opossum, Didelphis marsupialis, towards snake venom is due to antibothropic factors present in the blood serum, of which DM43 is one. It is responsible for the inhibition of the hemorrhagic activity of the venom. With a view to better understanding the mechanism of action of this protein against venom metalloproteases, one of the aims of the present work was to optimize the crystallization conditions of DM43 in order to determine its three-dimensional structure by X-ray diffraction. Crystallization trials revealed that ammonium sulphate was the best precipitant. Visualization and indexing of the diffraction patterns from such crystals only allowed for the determination of the unit cell parameters due to their inherently low quality. The values obtained were a = b = 117.34 (0.03) \'ANGSTRON\', c = 193.39 (0.02) Å, ?=?= 90° e ? = 120°, corresponding to the trigonal or hexagonal crystal systems. The recent determination of the amino acid sequence of DM43 permitted the homology modelling of its three-dimensional structure by satisfaction of spatial restraints. The three immunoglobulin-like domains of DM43 were modelled in two separate parts from the reference structure KIR2DL1 (1nkr), homologous to the two C-terminal domains of DM43, with which its shares 27.72% sequence identity. The N-terminal domain, denominated D0, was separately modelled based on the C-terminal domain of KIR2DL1, with which it shares 28.89% identity. The programs PATCHES and GRASP were used to detect the probable interface region between the two separate parts of the molecule as well as a region probably responsible for dimerisation. Polar residues in KIR2DL1 which had been substituted by hydrophobic residues in DM43 are observed concentrated on one face of the molecule devoid of glycosilation sites (D2) coinciding with the dimerisation interface observed in the growth hormone receptor. A structural motif characteristic of the haematopoetic receptor family, identified as the WSXWS box, was observed to some extent in all three domains of DM43 and most evident in domain D2. It is speculated that the existence of this motif is related to the relative orientation of the domains, by maintaining the first tryptophan of the motif positioned at the domain interface. An additional ?-strand (F) in D2, which is not characteristic of the immunoglobulin fold, is observed due to the presence of the conserved Pro273, three-residues prior to the WSXWS box. This strand appears to play an important role in correctly positioning the motif as it forms hydrogen bonds with strand G of the previous domain thus orientating the first tryptophan of the motif at the interface. The presence of hydrophobic residues at the interdomain interface, may also contribute to stabilizing the acute angular relationship between D1 and D2. An analogous interpretation to that given for the growth hormone receptor, suggests that the loops between ?-strands AB, CC\' and EF of domain D1 and between strands BC and FG do domain D2 plus the linker region, are involved in the binding of metalloproteinase by DM43.

Os venenos de serpentes são complexas misturas com proteínas e peptídeos que apresentam uma variedade de atividades biológicas. Devido à riqueza de seus componentes, várias moléculas encontradas no veneno vêm sendo utilizadas com fins terapêuticos, como agentes anticoagulantes ou analgésicos. Recentemente, diversos estudos têm mostrado que substâncias oriundas do veneno de serpentes são eficazes agentes antitumorais tanto in vivo quanto in vitro. Os estudos referentes ao veneno de C. vegrandis são escassos, o que o torna um interessante objeto de investigação para o isolamento de possíveis biomoléculas com potencial antitumorigênico. No presente trabalho analisamos este veneno com o intuito de isolar novas toxinas com atividade antitumoral. Observamos atividade em varias frações que apresentaram imunoreatividade frente a um anticorpo anti-jararagina, sugerindo a presença de metaloproteinases que, sabidamente, apresentam atividade contra certos tipos de tumores. Pela análise de seqüenciamento de novo foram identificadas sequencias peptídicas idênticas as encontradas na espécie C.durissus durissus. Foi identificada também uma fração ativa de baixo peso molecular que acreditamos ser um análogo à crotoxina que já foi relatada neste veneno. / Snake venoms are complex mixtures with proteins and peptides that have a variety of biological activities. Due to the high diversity of its components, several molecules found in the venom have been used for therapeutic purposes, such as anticoagulants or analgesics. Recently, several studies have shown that substances derived from snake venom are effective antitumor agents both in vivo and in vitro. The studies on the venom of C. vegrandis are scarce, turning it into an interesting object of investigation for the isolation of new biomolecules with potential antitumour potential. In this paper we analyzed this venom in order to isolate new toxins with antitumor activity. Cytotoxicity was detected in various fractions, and the most active showed immunoreactivity against an anti-jararrhagin, suggesting the presence of metalloproteases. Some toxins from this class have already been shown to be active against certain types of tumors. We also identified a low molecular weight active fraction of believed to be analogous to a crotoxin has already been in this venom.

Este trabalho investiga a influência de polimorfismos na região promotora do gene das metaloproteases 1, 3 e 8 na fisiopatogenia da insuficiência primária do tendão tibial posterior. A amostra de 150 pacientes selecionados é dividida em grupo-teste: 50 pacientes com diagnóstico clínico e anatomopatológico de tendinopatia do tendão tibial posterior e grupo-controle: 100 pacientes com tendão tibial posterior íntegro. O DNA dos voluntários é obtido a partir de células epiteliais da mucosa bucal mediante a extração com acetato de amônia. As técnicas de PCR e RFLP são utilizadas para análise dos genótipos. A análise estatística dos resultados é realizada pelo teste do qui-quadrado com nível de significância de 5%. Os resultados mostram que os polimorfismos -1607 da MMP-1 e -799 da MMP-8 estão relacionados com risco maior para tendinopatia primária do tendão tibial posterior, enquanto o polimorfismo -1612 da MMP-3 parece não influenciar essa tendinopatia / The aim of this study was to investigate the influence of polymorphisms in the promoter region of the gene of metalloproteinases 1, 3 and 8 in physiopatology of primary posterior tibial tendon insufficiency. The sample of 150 selected patients was divided into test group: 50 patients undergoing surgical procedures and pathological diagnosis of degenerative lesions of the posterior tibial tendon, and control group: 100 patients with posterior tibial tendon intact and no signs of degeneration. The DNA of the volunteers was obtained from oral mucosa epithelial cells, by extraction with ammonium acetate. PCR and RFLP were used for analysis of genotypes. Statistical analysis of results was performed by Chi-squared test with significance level of 5%. The results show that polymorphisms -1607 of MMP-1 and -799 of the MMP-8 are associated with increased risk for primary tendinopathy of the posterior tibial tendon, while the -1612 polymorphism of MMP-3 does not influence this tendinopathy

Neste trabalho descrevemos o isolamento, a caracterização funcional e estrutural de uma metaloprotease hemorrágica, denominada BjussuMP-I. A proteína foi isolada da peçonha de Bothrops jararacussu por combinação de dois passos cromatográficos, utilizando filtração molecular em Sephacryl S-200, equilibrada em tampão Tris-HCl (0,01 M, pH 7,0) seguida de cromatografia de interação hidrofóbica em Phenyl-Sepharose CL-4B, equilibrada em tampão Tris-HCl (0,01 M, pH 7,6 mais NaCl 4 M) e eluída com gradiente de NaCl (4-0 M) a 25°C no mesmo tampão. BjussuMP-I é uma proteína com massa molecular de 60 kDa e pI 5,6, a qual induziu hemorragia após injeção intradérmica em camundongos, com uma dose hemorrágica mínima (DHM) de 4,5 g. A atividade hemorrágica da BjussuMP-I foi totalmente inibida após incubação com um agente quelante (EDTA), confirmando a dependência de metal da enzima para esse efeito. BjussuMP-I possui atividade proteolítica sobre a caseína e fibrinogênio e nenhum efeito sobre a gelatina. Por outro lado, demonstrou alta especificidade pela cadeia do fibrinogênio enquanto que a cadeia somente foi hidrolisada na presença de altas concentrações da metaloprotease. A protease foi ativa sobre o fibrinogênio em pH neutro e alcalino e inativada a 75 °C. A dependência de metal da enzima foi demonstrada pela inibição exercida por EDTA, EGTA e 1,10 fenantrolina. Verificou-se uma inibição parcial pelo ?-mercaptoetanol e PMSF, enquanto que leupeptina e aprotinina não afetaram a atividade fibrinogenolítica. A enzima foi ativada na presença de íons Ca++ e Mg++, sendo inibida por Mn++, Fe++, Zn++, Co++ e Ni++. Além disso, baixas concentrações da enzima produziram lise no coágulo de fibrina. BjussuMP-I também demonstrou inibição da agregação plaquetária induzida por colágeno e ADP e atividade bactericida sobre Escherichia coli e Staphylococcus aureus. Verificou-se que as atividades hemorrágica e proteolítica da BjussuMP-I foram neutralizadas pelo diterpenóide clerodane (Bt-CD) de Bacharis trimera. Também se observou uma inibição total do efeito hemorrágico, utilizando o extrato aquoso de Pentaclethra macroloba (EPema). A enzima foi reconhecida por anticorpos antineuwiedase, com uma reação de identidade imunológica parcial. A seqüência completa do cDNA da BjussuMP-I com 1540 pb codificou para uma proteína de 547 resíduos de aminoácidos, que conservou os domínios comuns a metaloproteases hemorrágicas de alto peso molecular da classe PIII: (i) pré-pró-peptideo, (ii) metaloprotease, (iii) disintegrina-símile e (iv) domínio rico em cisteína. / In this study the isolation, functional and structural characterization of a hemorrhagic metalloprotease, named BjussuMP-I is reported. The protein was isolated from Bothrops jararacussu snake venom by a combination of two chromatographic steps, using gel filtration on Sephacryl S-200 (0.01 M Tris-HCl, pH7.6 buffer) and Phenyl-Sepharose CL-4B chromatography (0.01 M Tris-HCl plus 4 M NaCl, pH7.6 buffer) followed by a concentration gradient from 4 to 0 M NaCl at 25°C in the same buffer. BjussuMP-I is a 60 kDa protein with a pI 5.6, which induced hemorrhage after intradermal injection in mice with a minimum hemorrhagic dose (MHD) of 4.5 g. The hemorrhagic activity of BjussuMP-I was totally abolished after incubation with a chelating agent (EDTA), corroborating the metal-dependence of this effect. BjussuMP-I shows proteolytic activity on casein, collagen and fibrinogen, although no effect on gelatin was observed. In addition, it presented a high specificity toward the -chain of fibrinogen, while the -chain was only hydrolyzed at high concentrations of the metalloprotease. The protease was active against fibrinogen in neutral and alkaline pH and was inactivated at 75°C. The metal dependence of the enzyme was confirmed through inhibition by EDTA, EGTA and 1,10 phenantroline. A partial inhibition was observed with -mercaptoetanol and PMSF, while leupeptin and aprotinin did not inhibit the fibrinogenolytic activity. The enzyme was active in the presence of Ca++ and Mg++ and it was inhibited by Mn++, Fe++, Zn++, Co++ and Ni++. In addition, low concentrations of the enzyme presented lyses in fibrin plate after 12 h of incubation. BjussuMP-I also displayed inhibitory effect on collagen- and ADP-stimulated platelet aggregation, as well as bactericidal activity against Escherichia coli and Staphylococcus aureus. It was reported that both hemorrhagic and proteolytic activities of BjussuMP-I were neutralized by the clerodane diterpenoide (Bt-CD) from Bacharis trimera. Full inhibition of hemorrhage was also observed by using aqueous extract from Pentaclethra macroloba (EPema). The enzyme was recognized by anti-neuwiedase antibodies in a reaction of partial immunologic identity. The complete cDNA sequence of BjussuMP-I with 1540 pb encoded open reading frames of 547 amino acid residues which conserved the common domains of P-III high molecular weight hemorrhagic metalloproteases: (i) pre-pro-peptide, (ii) metalloprotease, (iii) disintegrin-like and (iv) rich cysteine domain.

Although transition metals are essential for life, misregulation of redox-active metal uptake, delivery, storage, and excretion has been linked with a series of neurodegenerative disorders. Alzheimer's disease (AD) is considered an epidemic and is the most widespread of all forms of dementia. Copper ions found in large concentrations localized in amyloid-ß plaques in the brain of AD patients have been linked with the generation of reactive oxygen species which are suspected to be the culprits leading to neuronal cell death. Herein a series of mechanistic and spectroscopic studies elucidate the chemistry about the metal-centered oxidation of biomolecules, including catecholamine neurotransmitters and some analogues by copper-complexes of amyloid-ß peptide. Transition metals can also be useful tools for characterization of metalloproteins due to their unique chemical and spectroscopic features. Herein a series of studies of the native Zn²+ and Cu²+-derivative of recombinant Blastula Protease 10 (BP10) from the sea urchin Paracentrotus lividus are presented in order to elucidate its catalytic mechanism, with the use of enzymology, metal substitution, and electronic absorption spectroscopy.