Structural similarities in glutaminyl- and methionyl-tRNA synthetases suggest a common overall orientation of tRNA binding.
AUTOR(ES)
Perona, J J
RESUMO
Detailed comparisons between the structures of the tRNA-bound Escherichia coli glutaminyl-tRNA (Gln-tRNA) synthetase [L-glutamine:tRNA(Gln) ligase (AMP-forming), EC 6.1.1.18] and recently refined E. coli methionyl-tRNA (Met-tRNA) synthetase [L-methionine:tRNA(Met) ligase (AMP-forming), EC 6.1.1.10] reveal significant similarities beyond the anticipated correspondence of their respective dinucleotide-fold domains. One similarity comprises a 23-amino acid alpha-helix-turn-beta-strand motif found in each enzyme within a domain that is inserted between the two halves of the dinucleotide binding fold. A second correspondence, which consists of two alpha-helices connected by a large loop and beta-strand, is located in the Gln-tRNA synthetase within a region that binds the inside corner of the "L"-shaped tRNA molecule. This structural motif contains a long alpha-helix, which extends along the entire length of the D and anticodon stems of the complexed tRNA. We suggest that the positioning of this helix relative to the dinucleotide fold plays a critical role in ensuring the proper global orientation of tRNA(Gln) on the surface of the enzyme. The structural correspondences suggest a similar overall orientation of binding of tRNA(Met) and tRNA(Gln) to their respective synthetases.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=51348Documentos Relacionados
- Selection of suppressor methionyl-tRNA synthetases: mapping the tRNA anticodon binding site.
- Involvement of the size and sequence of the anticodon loop in tRNA recognition by mammalian and E. coli methionyl-tRNA synthetases.
- Peptides at the tRNA binding site of the crystallizable monomeric form of E. coli methionyl-tRNA synthetase.
- Anticodon loop size and sequence requirements for recognition of formylmethionine tRNA by methionyl-tRNA synthetase.
- Induced fit of a peptide loop of methionyl-tRNA formyltransferase triggered by the initiator tRNA substrate