6c4h
From Proteopedia
Conformation of methylated GGQ in the peptidyl transferase center during translation termination (PTC region)
Structural highlights
Function[RL16_ECOLI] This protein binds directly to 23S ribosomal RNA and is located at the A site of the peptidyltransferase center. It contacts the A and P site tRNAs. It has an essential role in subunit assembly, which is not well understood.[HAMAP-Rule:MF_01342] [RL3_ECOLI] One of two assembly inititator proteins, it binds directly near the 3'-end of the 23S rRNA, where it nucleates assembly of the 50S subunit.[HAMAP-Rule:MF_01325_B] [RF2_ECOLI] Peptide chain release factor 2 directs the termination of translation in response to the peptide chain termination codons UGA and UAA.[HAMAP-Rule:MF_00094] [RL2_ECOLI] One of the primary rRNA binding proteins. Located near the base of the L1 stalk, it is probably also mobile. Required for association of the 30S and 50S subunits to form the 70S ribosome, for tRNA binding and peptide bond formation. It has been suggested to have peptidyltransferase activity; this is highly controversial.[HAMAP-Rule:MF_01320_B] In the E.coli 70S ribosome in the initiation state it has been modeled to make several contacts with the 16S rRNA (forming bridge B7b, PubMed:12809609); these contacts are broken in the model with bound EF-G.[HAMAP-Rule:MF_01320_B] Publication Abstract from PubMedThe universally conserved Gly-Gly-Gln (GGQ) tripeptide in release factors or release factor-like surveillance proteins is required to catalyze the release of nascent peptide in the ribosome. The glutamine of the GGQ is methylated post-translationally at the N(5) position in vivo; this covalent modification is essential for optimal cell growth and efficient translation termination. However, the precise conformation of the methylated-GGQ tripeptide in the ribosome remains unknown. Using cryoEM and X-ray crystallography, we report the conformation of methylated-GGQ in the peptidyl transferase center of the ribosome during canonical translational termination and co-translation quality control. It has been suggested that the GGQ motif arose independently through convergent evolution among otherwise unrelated proteins that catalyze peptide release. The requirement for this tripeptide in the highly conserved peptidyl transferase center suggests that the conformation reported here is likely shared during termination of protein synthesis in all domains of life. Conformation of methylated GGQ in the Peptidyl Transferase Center during Translation Termination.,Zeng F, Jin H Sci Rep. 2018 Feb 5;8(1):2349. doi: 10.1038/s41598-018-20107-8. PMID:29403017[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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