5aka

EM structure of ribosome-SRP-FtsY complex in closed state

Loading... Status: waiting for Mol* initialization Structural highlights 5aka is a 10 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 5.7Å Ligands: MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RL32_ECOLI Publication Abstract from PubMed The signal recognition particle (SRP)-dependent pathway is essential for correct targeting of proteins to the membrane and subsequent insertion in the membrane or secretion. In Escherichia coli, the SRP and its receptor FtsY bind to ribosome-nascent chain complexes with signal sequences and undergo a series of distinct conformational changes, which ensures accurate timing and fidelity of protein targeting. Initial recruitment of the SRP receptor FtsY to the SRP-RNC complex results in GTP-independent binding of the SRP-FtsY GTPases at the SRP RNA tetraloop. In the presence of GTP, a closed state is adopted by the SRP-FtsY complex. The cryo-EM structure of the closed state reveals an ordered SRP RNA and SRP M domain with a signal sequence-bound. Van der Waals interactions between the finger loop and ribosomal protein L24 lead to a constricted signal sequence-binding pocket possibly preventing premature release of the signal sequence. Conserved M-domain residues contact ribosomal RNA helices 24 and 59. The SRP-FtsY GTPases are detached from the RNA tetraloop and flexible, thus liberating the ribosomal exit site for binding of the translocation machinery. Ribosome-SRP-FtsY cotranslational targeting complex in the closed state.,von Loeffelholz O, Jiang Q, Ariosa A, Karuppasamy M, Huard K, Berger I, Shan SO, Schaffitzel C Proc Natl Acad Sci U S A. 2015 Mar 16. pii: 201424453. PMID:25775537 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribosome 3D structures Signal recognition particle receptor 3D structures

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