Functional involvement of a conserved motif in the middle region of the human ribosomal protein eL42 in translation.

Autor: Bulygin KN; Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk, 630090, Russia., Malygin AA; Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk, 630090, Russia., Graifer DM; Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk, 630090, Russia. Electronic address: graifer@niboch.nsc.ru.
Jazyk: angličtina
Zdroj: Biochimie [Biochimie] 2024 Mar; Vol. 218, pp. 96-104. Date of Electronic Publication: 2023 Sep 15.
DOI: 10.1016/j.biochi.2023.09.010
Abstrakt: Ribosomal protein eL42 (formerly known as L36A), a small protein of the large (60S) subunit of the eukaryotic ribosome, is a component of its exit (E) site. The residue K53 of this protein resides within the motif QSGYGGQTK mainly conserved in eukaryotes, and it is located in the immediate vicinity of the CCA-terminus of the ribosome-bound tRNA in the hybrid P/E state. To examine the role of this eL42 motif in translation, we obtained HEK293T cells producing the wild-type FLAG-tagged protein or its mutant forms with either single substitutions of conserved amino acid residues in the above motif, or simultaneous replacements in positions 45 and 51 or 45 and 53. Examination of the level of exogenous eL42 in fractions of polysome profiles from the target protein-producing cells by the Western blotting revealed that neither single substitution affects the assembly of 60S ribosomal subunits and 80S ribosomes or critically decreases the level of polysomes, but the latter was observed with the double replacements. Analysis of tRNAs bound to 80S ribosomes containing eL42 with double substitutions and examination their peptidyl transferase activity enabled estimation the stage of the elongation cycle, in which amino acid residues of the conserved eL42 motif are involved. We clearly show that cooperative interactions implicating the eL42 residues Q45, Q51, and K53 play a critical role in the ability of the human ribosome to perform properly elongation cycle at the step of deacylated tRNA dissociation from the E site in the human cell.
Competing Interests: Declaration of competing interest None.
(Copyright © 2023 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.)
Databáze: MEDLINE
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