Ribosome, aminoacyl-tRNA synthetases, genetic code, initiation/elongation/termination.
Translation
Translation
Ribosome-catalysed synthesis of polypeptide from mRNA template, decoded via aminoacyl-tRNAs. Initiation, elongation (peptidyl transfer +…
Ribosome
Universal ribozyme decoding mRNA and catalysing peptide-bond formation. Bacterial 70S = 30S + 50S; eukaryotic 80S = 40S + 60S. Peptidyl…
tRNA (transfer RNA)
~76-nt cloverleaf adaptor with 3′-CCA-A(A) acceptor arm (charged by aminoacyl-tRNA synthetases) and anticodon loop (pairs with mRNA codon).…
Aminoacyl-tRNA synthetase
Family of 20 enzymes (one per amino acid) that charge cognate tRNAs: aa + ATP + tRNA → aa-tRNA + AMP + PPi. Fidelity via editing domains;…
Genetic code
61 sense codons → 20 amino acids (redundant, mostly at 3rd position) + 3 stop codons. Nearly universal with minor variants (mitochondrial,…
Codon-anticodon pairing (wobble)
Watson-Crick pairing at codon positions 1-2 + relaxed (wobble) pairing at position 3 (Crick 1966) — explains codon redundancy with <64 tRNA…
Translation initiation
Bacterial: Shine-Dalgarno + fMet-tRNA + IF1-3. Eukaryotic: cap-dependent scanning (eIF4F + 40S·Met-tRNA·eIF2·GTP) from 5′ cap to…
Peptide-bond formation
Peptidyl transfer reaction catalysed by 23S/28S rRNA at the peptidyl-transferase centre. Nucleophilic attack by A-site α-amino on P-site…
Translation elongation
EF-Tu delivers aa-tRNA; peptidyl transferase forms peptide bond; EF-G translocates ribosome. Repeats until stop codon. ~20 aa/sec in…
Translation termination
Stop codon UAA/UAG/UGA recognised by release factors (RF1/2 bacterial, eRF1 eukaryotic) which hydrolyse the peptidyl-tRNA bond. Ribosome…
Ribosomal translation-fidelity framework
Ribosomes incorporate amino acids with error rate ~10⁻³ to 10⁻⁴ per codon via two-step kinetic proofreading (Hopfield 1974; Ninio 1975):…
Codon-usage bias / tRNA-pool optimisation framework
Synonymous codons are not equiprobable: codon-usage frequencies correlate with tRNA-pool abundances via translational selection. CAI…
Genetic code (Nirenberg 1961)
Nirenberg-Matthaei 1961 (Nobel 1968) UUU codes Phe; modern code-deviations mitochondria + Mycoplasma; codon-optimization.
Ribosome (Nobel 2009)
Yonath-Ramakrishnan-Steitz Nobel 2009 ribosome atomic-structures; modern cryo-EM resolution + antibiotic-target.
tRNA (Zamecnik 1958)
P Zamecnik 1958 tRNA discovery; modern 20 aminoacyl-tRNA-synthetase classes + class-I/II + non-canonical AAs.
Translation initiation
Pelletier-Sonenberg 1988 IRES + cap-dependent + cap-independent; modern translational-control eIF4F + 4E-BP + mTOR.
RQC (Brandman 2012)
Brandman-Hegde 2012 ribosome-quality-control; modern Ltn1 + NEMF + ZNF598 surveillance pathways.
Ribo-seq (Ingolia 2009)
Ingolia-Weissman 2009 ribosome-profiling; modern translation-rate + uORF + ribo-seq atlas.
Adaptor hypothesis (Crick 1957)
F Crick 1957 (Nobel 1962) adaptor-hypothesis; modern tRNA-mediated codon-anticodon + 64-codon code Khorana-Holley 1968.
Ribosome (Yonath 2009)
A Yonath-V Ramakrishnan-T Steitz 2009 (Nobel 2009) 70S-ribosome 1.5Å crystal; modern cryo-EM 2.0Å + tRNA-translocation movies.
Wobble (Crick 1966)
F Crick 1966 wobble-hypothesis 3rd-codon-position relaxation; modern modified-tRNA modifications + tRNA-fidelity codon-bias.
EF-Tu (Jurnak 1985)
F Jurnak 1985 EF-Tu-GTPase + Forster-Wittinghofer kirromycin; modern GTP-hydrolysis + tRNA-proofreading kinetics.
IRES (Pelletier-Sonenberg 1988)
J Pelletier-N Sonenberg 1988 IRES-poliovirus; modern HCV-IRES + cap-independent + cellular-IRES + COVID-mRNA-protection.
NMD (Leeds 1991)
P Leeds-M Culbertson 1991 NMD-yeast; modern UPF1-2-3 ATPase-dependent surveillance + therapeutic-readthrough ataluren CF.