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Functional and structural studies of peroxiredoxin I from Leishmania braziliensis and Homo sapiens aiming to understand the oligomerization and catalysis mechanisms

Grant number: 12/24134-3
Support Opportunities:Scholarships in Brazil - Doctorate (Direct)
Effective date (Start): July 01, 2013
Effective date (End): November 30, 2016
Field of knowledge:Biological Sciences - Biochemistry
Principal Investigator:Mário Tyago Murakami
Grantee:Mariana Abrahão Bueno de Morais
Host Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Ministério da Ciência, Tecnologia e Inovação (Brasil). Campinas , SP, Brazil
Associated scholarship(s):15/05851-4 - Functional characterization of the mitochondrial peroxiredoxin I from Leishmania braziliensis evaluating the peroxidase and chaperone activity, BE.EP.DD


Leishmaniasis are caused by protozoan parasites of the genus Leishmania and transmitted by sandflies insects. This disease affects about 350 million people in 88 countries. Since Leishmania is an intracellular parasite, the existence of efficient mechanisms for avoidance of toxic molecules such as reactive oxygen and nitrogen, is crucial to the ability of the parasite survival and replication in host cells. The tryparedoxina peroxidase (TXNPx) is a member of the subfamily I of peroxiredoxins (PRX-I) participating in an enzymatic cascade for the detoxification of hydroperoxides. Studies show that this enzyme is essential for the survival of Leishmania sp during oxidative stress generated by macrophages and their overexpression results in increased growth rate, doubling time lower and a higher resistance to oxidative stress in the parasite. To date, the structures resolved PRX-I exhibit three crystalline forms possible: decamer, and the decamer-dimer. The change in state between a quaternary dimer structure and a ring-shaped (or decamer-decamer) is described as important to its function and cellular location. Data in the literature indicate the role of ionic strength, pH, and redox state of the protein concentration in the oligomerization of PRX-I. In undergraduate research project (FAPESP 2011/10248-4), cloning and expression of mitochondrial Leishmania braziliensis TXNPx (LbTXNPx) were performed in a prokaryotic system, as well as the purification and crystallization of the protein. The crystal diffracted to 3.0 Å resolution and a dimer was found in the asymmetric unit. Furthermore, we found that the presence of calcium ions resulted in decameric forms of LbTXNPx. This PhD project aims to continue the project FAPESP 2011/10248-4, and aims to determine and refine the structure of dimeric LbTXNPx, refine the crystals in order to improve the resolution of the structure, crystallization LbTXNPx in the presence of calcium ions and resolution this structure, identification of residues crucial for calcium binding, the analysis of the influence of calcium on enzyme activity and verify the universality of this mechanism for oligomerization. (AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
MORAIS, MARIANA A. B.; GIUSEPPE, PRISCILA O.; SOUZA, TATIANA A. C. B.; CASTRO, HELENA; HONORATO, RODRIGO V.; OLIVEIRA, PAULO S. L.; NETTO, LUIS E. S.; TOMAS, ANA M.; MURAKAMI, MARIO T.. Calcium and magnesium ions modulate the oligomeric state and function of mitochondrial 2-Cys peroxiredoxins in Leishmania parasites. Journal of Biological Chemistry, v. 292, n. 17, p. 7023-7039, . (15/05851-4, 11/10248-4, 10/51730-0, 12/24134-3)
MORAIS, MARIANA A. B.; GIUSEPPE, PRISCILA O.; SOUZA, TATIANA A. C. B.; ALEGRIA, THIAGO G. P.; OLIVEIRA, MARCOS A.; NETTO, LUIS E. S.; MURAKAMI, MARIO T.. How pH Modulates the Dimer-Decamer Interconversion of 2-Cys Peroxiredoxins from the Prx1 Subfamily. Journal of Biological Chemistry, v. 290, n. 13, p. 8582-8590, . (11/10248-4, 10/51730-0, 12/24134-3)
Academic Publications
(References retrieved automatically from State of São Paulo Research Institutions)
MORAIS, Mariana Abrahão Bueno de. Ca2+, Mg2+ and pH integrate novel regulatory mechanisms of structure and function of mitochondrial peroxiredoxins from Leishmania contributing to parasite survival. 2016. Doctoral Thesis - Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia Campinas, SP.

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