1mvr
From Proteopedia
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Decoding Center & Peptidyl transferase center from the X-ray structure of the Thermus thermophilus 70S ribosome, aligned to the low resolution Cryo-EM map of E.coli 70S Ribosome
Overview
Protein synthesis takes place on the ribosome, where genetic information carried by messenger RNA is translated into a sequence of amino acids. This process is terminated when a stop codon moves into the ribosomal decoding centre (DC) and is recognized by a class-1 release factor (RF). RFs have a conserved GGQ amino-acid motif, which is crucial for peptide release and is believed to interact directly with the peptidyl-transferase centre (PTC) of the 50S ribosomal subunit. Another conserved motif of RFs (SPF in RF2) has been proposed to interact directly with stop codons in the DC of the 30S subunit. The distance between the DC and PTC is approximately 73 A. However, in the X-ray structure of RF2, SPF and GGQ are only 23 A apart, indicating that they cannot be at DC and PTC simultaneously. Here we show that RF2 is in an open conformation when bound to the ribosome, allowing GGQ to reach the PTC while still allowing SPF-stop-codon interaction. The results indicate new interpretations of accuracy in termination, and have implications for how the presence of a stop codon in the DC is signalled to PTC.
About this Structure
1MVR is a Protein complex structure of sequences from Escherichia coli. Full crystallographic information is available from OCA.
Reference
A cryo-electron microscopic study of ribosome-bound termination factor RF2., Rawat UB, Zavialov AV, Sengupta J, Valle M, Grassucci RA, Linde J, Vestergaard B, Ehrenberg M, Frank J, Nature. 2003 Jan 2;421(6918):87-90. PMID:12511960
Page seeded by OCA on Thu Mar 20 12:48:47 2008
