Lys53 of Ribosomal Protein L36AL and the CCA End of atRNA at the P/E Hybrid Site Are in Close Proximity on the Human Ribosome
Résumé
Previously we have shown that the CCA end of aP-tRNA can be crosslinked with the RPL36ALprotein of the large subunit of mammalian ribosomes;itbelongs to the L44e protein family presentina ll eukaryotic andarchaeal ribosomes. Here we confirm and extend this finding and demonstrate that: 1) this crosslink is specific for atRNA at the P/E hybrid site, as atRNA in all other tRNA positions of pre-translocational ribosomes could not be crosslinked with aribosomal protein, 2) the crosslink was formed most efficiently with C74 and C75 of P/E-tRNA, but could also connectt he ultimateAof this
tRNA with Lys53 of protein RPL36AL, 3) this protein contains seven monomethylated residues (three lysyl and three arginyl residues,asw ell as glutaminyl residue 51), 4) Q51 is part of aconserved GGQ motif in the L44e proteins in eukaryotic 80S ribosomes that is identical to the universally conserved motif of release factors implicated in promoting peptidyl-tRNA hydrolysis, and 5) the large number of modifications, in which some of the residues were methylated to about50%,might indicatethat protein RPL36AL is apreferential target for regulation.
Domaines
Biochimie, Biologie Moléculaire
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