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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Selenocysteine biosynthesis and insertion machinery in Naegleria gruberi

Texto completo
Autor(es):
da Silva, M. T. A. [1] ; Caldas, V. E. A. [1] ; Costa, F. C. [1] ; Silvestre, D. A. M. M. [2] ; Thiemann, O. H. [1]
Número total de Autores: 5
Afiliação do(s) autor(es):
[1] IFSC USP, Lab Prot Crystallog & Struct Biol, BR-13560970 Sao Carlos, SP - Brazil
[2] Univ Sao Paulo, Fac Med, Hosp Clin, BR-05403000 Sao Paulo - Brazil
Número total de Afiliações: 2
Tipo de documento: Artigo Científico
Fonte: Molecular and Biochemical Parasitology; v. 188, n. 2, p. 87-90, APR 2013.
Citações Web of Science: 8
Resumo

Selenium (Se) is an essential trace element primarily found in selenoproteins as the 21st amino acid (selenocysteine, Sec, or U). Selenoproteins play an important role in growth and proliferation and are typically involved in cellular redox balance. Selenocysteine is encoded by an in-frame UGA codon specified by a stem-loop structure, the Sec insertion sequence element (SECIS), which, in eukaryotes, is located in the 3'-untranslated region (UTR). The availability of the Naegleria gruberi (ATCC 30224) genome sequence and the use of this organism as a model system for the pathogenic amoeba N. fowleri allowed us to investigate the Sec incorporation pathway in this primitive eukaiyote. Using bioinformatics tools, we identified gene sequences encoding PSTK (O-phosphoseryl-tRNA(Sec) kinase), SepSecS (O-phosphoseryl-tRNA:selenocysteinyl-tRNA synthase), SelD/SPS2 (selenophosphate synthetase), EFSec (selenocysteine-specific elongation factor) and SBP (SECIS binding protein). These findings were confirmed by RT-PCR and by sequencing. A potential tRNA(sec)(ser) (SeIC) gene and a putative selenoprotein with sequence similarity to a mitochondrial thioredoxin reductase (TR3) were also identified. Our results show that the selenocysteine incorporation machinery is indeed present in N. gruberi. Interestingly, the SelD/SPS2 gene is 2214 bp in length and contains two distinct domains. The N-terminal region shows sequence similarity to predicted methyltransferase proteins, and the C-terminal region is homologous to prokaryotic Se1D/SPS2. Our results suggest the possibility of novel selenoproteins. (C) 2013 Elsevier B.V. All rights reserved. (AU)

Processo FAPESP: 98/14138-2 - Center for Structural Molecular Biotechnology
Beneficiário:Glaucius Oliva
Linha de fomento: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs