6i0y

TnaC-stalled ribosome complex with the titin I27 domain folding close to the ribosomal exit tunnel

Loading... Status: waiting for Mol* initialization Structural highlights 6i0y is a 10 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.2Å Ligands: MG, TRP, ZN 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 Proteins that fold cotranslationally may do so in a restricted configurational space, due to the volume occupied by the ribosome. How does this environment, coupled with the close proximity of the ribosome, affect the folding pathway of a protein? Previous studies have shown that the cotranslational folding process for many proteins, including small, single domains, is directly affected by the ribosome. Here, we investigate the cotranslational folding of an all-beta Ig domain, titin I27. Using an arrest peptide-based assay and structural studies by cryo-EM, we show that I27 folds in the mouth of the ribosome exit tunnel. Simulations that use a kinetic model for the force dependence of escape from arrest accurately predict the fraction of folded protein as a function of length. We used these simulations to probe the folding pathway on and off the ribosome. Our simulations-which also reproduce experiments on mutant forms of I27-show that I27 folds, while still sequestered in the mouth of the ribosome exit tunnel, by essentially the same pathway as free I27, with only subtle shifts of critical contacts from the C to the N terminus. Folding pathway of an Ig domain is conserved on and off the ribosome.,Tian P, Steward A, Kudva R, Su T, Shilling PJ, Nickson AA, Hollins JJ, Beckmann R, von Heijne G, Clarke J, Best RB Proc Natl Acad Sci U S A. 2018 Nov 27;115(48):E11284-E11293. doi:, 10.1073/pnas.1810523115. Epub 2018 Nov 9. PMID:30413621 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribosome 3D structures Titin 3D structures

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