3deg

Complex of elongating Escherichia coli 70S ribosome and EF4(LepA)-GMPPNPComplex of elongating Escherichia coli 70S ribosome and EF4(LepA)-GMPPNP

3deg, resolution 10.90Å Show:Asymmetric Unit Biological Assembly Structural highlights 3deg is a 11 chain structure with sequence from Ecoli and Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Gene: lepA, b2569, JW2553 (ECOLI) Experimental data: Check Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed EF4 (LepA) is an almost universally conserved translational GTPase in eubacteria. It seems to be essential under environmental stress conditions and has previously been shown to back-translocate the tRNAs on the ribosome, thereby reverting the canonical translocation reaction. In the current work, EF4 was directly visualized in the process of back-translocating tRNAs by single-particle cryo-EM. Using flexible fitting methods, we built a model of ribosome-bound EF4 based on the cryo-EM map and a recently published unbound EF4 X-ray structure. The cryo-EM map establishes EF4 as a noncanonical elongation factor that interacts not only with the elongating ribosome, but also with the back-translocated tRNA in the A-site region, which is present in a previously unseen, intermediate state and deviates markedly from the position of a canonical A-tRNA. Our results, therefore, provide insight into the underlying structural principles governing back-translocation. A new tRNA intermediate revealed on the ribosome during EF4-mediated back-translocation.,Connell SR, Topf M, Qin Y, Wilson DN, Mielke T, Fucini P, Nierhaus KH, Spahn CM Nat Struct Mol Biol. 2008 Sep;15(9):910-5. PMID:19172743 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Elongation factor 3D structures Escherichia coli LepA%2C the ribosomal back translocase GTP-binding protein 3D structures Ribosomal protein L11 Transfer RNA (tRNA)