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Adenosine binding to low-molecular-weight purine nucleoside phosphorylase: the structural basis for recognition based on its complex with the enzyme from Schistosoma mansoni

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Autor(es):
Pereira, Humberto M. ; Rezende, Martha M. ; Castilho, Marcelo Santos ; Oliva, Glaucius ; Garratt, Richard C.
Número total de Autores: 5
Tipo de documento: Artigo Científico
Fonte: ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY; v. 66, p. 7-pg., 2010-01-01.
Resumo

Schistosomes are unable to synthesize purines de novo and depend exclusively on the salvage pathway for their purine requirements. It has been suggested that blockage of this pathway could lead to parasite death. The enzyme purine nucleoside phosphorylase (PNP) is one of its key components and molecules designed to inhibit the low-molecular-weight (LMW) PNPs, which include both the human and schistosome enzymes, are typically analogues of the natural substrates inosine and guanosine. Here, it is shown that adenosine both binds to Schistosoma mansoni PNP and behaves as a weak micromolar inhibitor of inosine phosphorolysis. Furthermore, the first crystal structures of complexes of an LMW PNP with adenosine and adenine are reported, together with those with inosine and hypoxanthine. These are used to propose a structural explanation for the selective binding of adenosine to some LMW PNPs but not to others. The results indicate that transition-state analogues based on adenosine or other 6-amino nucleosides should not be discounted as potential starting points for alternative inhibitors. (AU)

Processo FAPESP: 98/14138-2 - Center for Structural Molecular Biotechnology
Beneficiário:Glaucius Oliva
Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
Processo FAPESP: 06/60280-3 - Ensaios de inibição enzimática e cristalografia de alvos protéicos de parasitas tropicais
Beneficiário:Humberto D'Muniz Pereira
Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado