4v4v

Structure of a pre-translocational E. coli ribosome obtained by fitting atomic models for RNA and protein components into cryo-EM map EMD-1056Structure of a pre-translocational E. coli ribosome obtained by fitting atomic models for RNA and protein components into cryo-EM map EMD-1056

4v4v, resolution 15.00Å Show:Asymmetric Unit Biological Assembly Structural highlights 4v4v is a 12 chain structure with sequence from Escherichia coli. This structure supersedes the now removed PDB entries 2gy9 and 2gya. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Experimental data: Check Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RL24_ECOLI One of two assembly initiator proteins, it binds directly to the 5'-end of the 23S rRNA, where it nucleates assembly of the 50S subunit. It is not thought to be involved in the functions of the mature 50S subunit in vitro. One of the proteins that surrounds the polypeptide exit tunnel on the outside of the subunit. Publication Abstract from PubMed In E. coli, the SecM nascent polypeptide causes elongation arrest, while interacting with 23S RNA bases A2058 and A749-753 in the exit tunnel of the large ribosomal subunit. We compared atomic models fitted by real-space refinement into cryo-electron microscopy reconstructions of a pretranslocational and SecM-stalled E. coli ribosome complex. A cascade of RNA rearrangements propagates from the exit tunnel throughout the large subunit, affecting intersubunit bridges and tRNA positions, which in turn reorient small subunit RNA elements. Elongation arrest could result from the inhibition of mRNA.(tRNAs) translocation, E site tRNA egress, and perhaps translation factor activation at the GTPase-associated center. Our study suggests that the specific secondary and tertiary arrangement of ribosomal RNA provides the basis for internal signal transduction within the ribosome. Thus, the ribosome may itself have the ability to regulate its progression through translation by modulating its structure and consequently its receptivity to activation by cofactors. Elongation arrest by SecM via a cascade of ribosomal RNA rearrangements.,Mitra K, Schaffitzel C, Fabiola F, Chapman MS, Ban N, Frank J Mol Cell. 2006 May 19;22(4):533-43. PMID:16713583 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribosome 3D structures Transfer RNA (tRNA)