PATRICK JACK SPENCER

Resumo

Possui graduação em Ciências Biológicas pela Universidade Presbiteriana Mackenzie (1991), mestrado em Tecnologia Nuclear pela Universidade de São Paulo (1995) e doutorado em Tecnologia Nuclear pela Universidade de São Paulo (2000) tendo sido bolsista sandwich no US Army Medical Research Institute for Infeccious Diseases (98-99). É responsável pelo Biotério de criação e manutenção de animais de laboratório do IPEN. Tem experiência na área de Bioquímica, com ênfase em Proteínas, atuando principalmente nos seguintes temas: veneno, proteínas, bothrops, irradiação e miotoxina.(Texto extraído do Currículo Lattes em 22 dez. 2021)

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Agora exibindo 1 - 8 de 8
  • Artigo IPEN-doc 27113
    Molecular model of cytotoxin-1 from Naja mossambica mossambica venom in complex with chymotrypsin
    2015 - MUNAWAR, AISHA; AKREM, AHMED; HUSSAIN, ASHIQ; SPENCER, PATRICK; BETZEL, CHRISTIAN
    Snake venom is a myriad of biologically active proteins and peptides. Three finger toxins are highly conserved in their molecular structure, but interestingly possess diverse biological functions. During the course of evolution the introduction of subtle mutations in loop regions and slight variations in the three dimensional structure, has resulted in their functional versatility. Cytotoxin-1 (UniProt ID: P01467), isolated from Naja mossambica mossambica, showed the potential to inhibit chymotrypsin and the chymotryptic activity of the 20S proteasome. In the present work we describe a molecular model of cytotoxin- 1 in complex with chymotrypsin, prepared by the online server ClusPro. Analysis of the molecular model shows that Cytotoxin-1 (P01467) binds to chymotrypsin through its loop I located near the N-terminus. The concave side of loop I of the toxin fits well in the substrate binding pocket of the protease. We propose Phe10 as the dedicated P1 site of the ligand. Being a potent inhibitor of the 20S proteasome, cytotoxin-1 (P01467) can serve as a potential antitumor agent. Already snake venom cytotoxins have been investigated for their ability as an anticancer agent. The molecular model of cytotoxin-1 in complex with chymotrypsin provides important information towards understanding the complex formation.
  • Artigo IPEN-doc 25830
    The amphibian diacylglycerol O-acyltransferase 2 (DGAT2)
    2019 - SCIANI, JULIANA M.; NEVES, ADRIANA; VASSÃO, RUTH C.; SPENCER, PATRICK; ANTONIAZZI, MARTA M.; JARED, CARLOS; PIMENTA, DANIEL C.
    Amphibians are, currently, considered the first vertebrates that had performed the aquatic to terrestrial transition during evolution; therefore, water balance and dehydration control were prerequisites for such environment conquering. Among anurans, Phyllomedusa is a well-studied genus, due to its peptide-rich skin secretion. Here, we have analyzed the skin secretion of Phyllomedusa distincta targeting the proteins present in the skin secretion. The major soluble protein was chromatographically isolated and utilized to immunize rabbits. Through proteomics approaches, we were able to identify such protein as being the diacylglycerol O-acyltransferase 2 (DGAT2), a crucial enzyme involved in lipid synthesis and in the skin water balance. Immunohistochemistry assays revealed the protein tissular distribution for different animal species, belonging to different branches of the phylogenetic tree. Specifically, there was positivity to the anti-DGAT2 on Amphibians’ skin, and no antibody recognition on fish and mammals’ skins. The DGAT2 multiple sequence alignment reveals some degree of conservation throughout the genera; however, there is a different cysteine pattern among them. Molecular modeling analyses corroborate that the different cysteine pattern leads to distinct 3D structures, explaining the different antibody recognition. Moreover, the protein phylogenetic analyses place the Xenopus DGAT2 (the available amphibian representative) next to the Coelacanthus enzyme, which have led the authors to term this a ‘paleo-protein’. DGAT2 would be, therefore, an ancient protein, crucial to the terrestrial environment conquest, with a unique folding—as indicated by the molecular models and immunohistochemistry analyses—a consequence of the different cysteine pattern but with conserved biological function.
  • Artigo IPEN-doc 25112
    Biochemical analyses of proteins from duttaphrynus melanostictus (Bufo melanostictus) skin secretion
    2018 - MARIANO, DOUGLAS O.C.; MESSIAS, MARCELA Di G.; PREZOTTO-NETO, JOSE P.; SPENCER, PATRICK J.; PIMENTA, DANIEL C.
    A crucial step in scientific analysis can be sample preparation, and its importance increases in the same rate as the sensitivity of the following employed/desired analytical technique does. The need to analyze complex, viscous matrices is not new, and diverse approaches have been employed, with different success rates depending on the intended molecules. Solid-phase extraction, for example, has been successfully used in sample preparation for organic molecules and peptides. However, due to the usual methodological conditions, biologically active proteins are not successfully retrieved by this technique, resulting in a low rate of protein identification reported for the viscous amphibian skin secretion. Here we describe an ion-exchange batch processing sample preparation technique that allows viscous or adhesive materials (as some amphibian skin secretions) to be further processed by classical liquid chromatography approaches. According to our protocol, samples were allowed to equilibrate with a specific resin that was washed with appropriated buffers in order to yield the soluble protein fraction. In order to show the efficiency of our methodology, we have compared our results to classically prepared skin secretion, i.e., by means of filtration and centrifugation. After batch sample preparation, we were able to obtain reproductive resolved protein chromatographic profiles, as revealed by SDS-PAGE, and retrieve some biological activities, namely, hydrolases belonging to serine peptidase family. Not only that, but also the unbound fraction was rich in low molecular mass molecules, such as alkaloids and steroids, making this sample preparation technique also suitable for the enrichment of such molecules.
  • Artigo IPEN-doc 20886
    New insights into the structural characteristics of irradiated crotamine
    2015 - OLIVEIRA, KARINA C.; SPENCER, PATRICK J.; FERREIRA JUNIOR, RUI S.; NASCIMENTO, NANCI
  • Artigo IPEN-doc 20245
    Crystallization and preliminary X-ray diffraction studies of an L-amino-acid oxidase from Lachesis multa venom
    2014 - ULLAH, ANWAR; MASOOD, REHANA; SPENCER, PATRICK J.; MURAKAMI, MARIO T.; ARNI, RAGHUVIR K.
  • Artigo IPEN-doc 14253
    Radiation stability of resveratrol in immobilization on poly vinyl pyrrolidone hydrogel dressing for dermatological use
    2010 - MOMESSO, ROBERTA G.R.A.P.; MORENO, CAROLINA S.; ROGERO, SIZUE O.; ROGERO, JOSE R.; SPENCER, PATRICK J.; LUGAO, ADEMAR B.
  • Artigo IPEN-doc 14835
    Structure alteration and immunological properties of sup(60)Co-gamma-rays irradiated bothropstoxin-I
    2010 - BAPTISTA, J.A.; VIEIRA, D.P.; GALISTEO JUNIOR, A.J.; HIGA, O.Z.; CASARE, M.; YONAMINE, C.M.; CAPRONI, P.; CAMPOS, L.A.; ANDRADE JUNIOR, H.F. de; SPENCER, P.J.; NASCIMENTO, N.
  • Artigo IPEN-doc 18331
    Purification, crystallization and preliminary X-ray diffraction analysis of crotamine, a myotoxic polypeptide from the Brazilian snake Crotalus durissus terrificus
    2012 - CORONADO, MONIKA A.; GEORGIEVA, DESSISLAVA; BUCK, FRIEDRICH; GABDOULKHAKOV, AZAT H.; ULLAH, ANWAR; SPENCER, PATRICK J.; ARNI, RAGHUVIR K.; BETZEL, CHRISTIAN