title: Inhibitory effects promoted by 5'-nucleotides on the ecto-3'-nucleotidase activity of Leishmania amazonensis.
abstract: The protozoan parasite Leishmania amazonensis is the etiological agent of cutaneous leishmaniasis. During its life cycle, the flagellated metacyclic promastigote forms are transmitted to vertebrate hosts by sandfly bites, and they develop into amastigotes inside macrophages, where they multiply. L. amazonensis possesses a bifunctional enzyme, called 3'-nucleotidase/nuclease (3'NT/NU), which is able to hydrolyze extracellular 3'-monophosphorylated nucleosides and nucleic acids. 3'NT/NU plays an important role in the generation of extracellular adenosine and has been described as a key enzyme in the acquisition of purines by trypanosomatids. Furthermore, it has been observed that 3'NT/NU also plays a valuable role in the establishment of parasitic infection. In this context, this study aimed to investigate the modulation of the 3'-nucleotidase (3'NT) activity of L. amazonensis by several nucleotides. It was observed that 3'NT activity is inhibited by micromolar concentrations of guanosine and guanine nucleotides. The inhibition promoted by 5'-GMP on the 3'NT activity of L. amazonensis is reversible and uncompetitive because the addition of the inhibitor decreased the kinetic parameters Km and Vmax. Finally, we found that the addition of 5'-GMP is able to reverse the stimulation promoted by 3'-AMP in a macrophage-parasite interaction assay. The determination of compounds that can inhibit the 3'NT activity of Leishmania is very important because this enzyme does not occur in mammals, making it a potential therapeutic target.
authors.affiliation: Instituto de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, 21941-590, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, 21941-590, Rio de Janeiro, RJ, Brazil.
authors.forename: Anita Leocadio
authors.initials: AL
authors.lastname: Freitas-Mesquita
authors.affiliation: Instituto de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, 21941-590, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, 21941-590, Rio de Janeiro, RJ, Brazil.
authors.forename: Marta T
authors.initials: MT
authors.lastname: Gomes
authors.affiliation: Instituto de Microbiologia Prof. Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil.
authors.forename: Danielle P
authors.initials: DP
authors.lastname: Vieira
authors.affiliation: Instituto de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, 21941-590, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, 21941-590, Rio de Janeiro, RJ, Brazil.
authors.forename: Lisvane
authors.initials: L
authors.lastname: Paes-Vieira
authors.affiliation: Instituto de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, 21941-590, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, 21941-590, Rio de Janeiro, RJ, Brazil.
authors.forename: Michelle T C
authors.initials: MT
authors.lastname: Nascimento
authors.affiliation: Instituto de Microbiologia Prof. Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ, 21941-590, Brazil.
authors.forename: Angela H C S
authors.initials: AH
authors.lastname: Lopes
authors.affiliation: Instituto de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, 21941-590, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, 21941-590, Rio de Janeiro, RJ, Brazil. Electronic address: meyer@bioqmed.ufrj.br.
authors.forename: José Roberto
authors.initials: JR
authors.lastname: Meyer-Fernandes
mesh_terms: D000818:Animals; D006153:Guanosine Diphosphate / Q000494:pharmacology*; D006157:Guanosine Monophosphate / Q000494:pharmacology*; D006160:Guanosine Triphosphate / Q000494:pharmacology*; D007700:Kinetics; D007894:Leishmania mexicana / Q000187:drug effects / Q000201:enzymology*; D008264:Macrophages / Q000469:parasitology; D051379:Mice; D009708:Nucleotidases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000067996:RAW 264.7 Cells
chemical_list: D006153:Guanosine Diphosphate; D006157:Guanosine Monophosphate; D006160:Guanosine Triphosphate; D009708:Nucleotidases; C040470:3'-nucleotidase
keywords: 3′-AMP; 5′-GMP; Ecto-3′-nucleotidase; Extracellular nucleotides; Leishmania amazonensis; Uncompetitive inhibition