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Sustenance of Escherichia coli on a single tRNAMet.
Govindan, Ashwin; Ayyub, Shreya Ahana; Varshney, Umesh.
Afiliação
  • Govindan A; Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India.
  • Ayyub SA; Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India.
  • Varshney U; Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India.
Nucleic Acids Res ; 46(21): 11566-11574, 2018 11 30.
Article em En | MEDLINE | ID: mdl-30256973
Living organisms possess two types of tRNAs for methionine. Initiator tRNAs bind directly into the ribosomal P-site to initiate protein synthesis, and the elongators bind to the A-site during the elongation step. Eubacterial initiators (tRNAfMet) are unique in that the methionine attached to them is formylated to facilitate their binding to initiation factor 2 (IF2), and to preclude them from binding to elongation factor Tu (EFTu). However, in mammalian mitochondria, protein synthesis proceeds with a single dual function tRNAMet. Escherichia coli possesses four tRNAfMet (initiator) and two tRNAMet (elongator) genes. Free-living organisms possessing the mitochondrion like system of single tRNAMet are unknown. We characterized mutants of E. coli tRNAfMet that function both as initiators and elongators. We show that some of the tRNAfMet mutants sustain E. coli lacking all four tRNAfMet and both tRNAMet genes, providing a basis for natural occurrence of mitochondria like situation in free living organisms. The tRNA mutants show in vivo binding to both IF2 and EFTu, indicating how they carry out these otherwise mutually exclusive functions by precise regulation of their in vivo formylation. Our results provide insights into how distinct initiator and elongator methionine tRNAs might have evolved from a single 'dual function' tRNA.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: RNA de Transferência de Metionina / Escherichia coli / Mutação Idioma: En Revista: Nucleic Acids Res Ano de publicação: 2018 Tipo de documento: Article País de afiliação: Índia País de publicação: Reino Unido

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: RNA de Transferência de Metionina / Escherichia coli / Mutação Idioma: En Revista: Nucleic Acids Res Ano de publicação: 2018 Tipo de documento: Article País de afiliação: Índia País de publicação: Reino Unido