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2iy3
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(New page: 200px<br /><applet load="2iy3" size="450" color="white" frame="true" align="right" spinBox="true" caption="2iy3, resolution 16.0Å" /> '''STRUCTURE OF THE E. ...)
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Revision as of 10:20, 21 November 2007
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STRUCTURE OF THE E. COLI SIGNAL RECOGNITION PARTICLE BOUND TO A TRANSLATING RIBOSOME
Overview
The prokaryotic signal recognition particle (SRP) targets membrane, proteins into the inner membrane. It binds translating ribosomes and, screens the emerging nascent chain for a hydrophobic signal sequence, such, as the transmembrane helix of inner membrane proteins. If such a sequence, emerges, the SRP binds tightly, allowing the SRP receptor to lock on. This, assembly delivers the ribosome-nascent chain complex to the protein, translocation machinery in the membrane. Using cryo-electron microscopy, and single-particle reconstruction, we obtained a 16 A structure of the, Escherichia coli SRP in complex with a translating E. coli ribosome, containing a nascent chain with a transmembrane helix anchor. We also, obtained structural information on the SRP bound to an empty E. coli, ribosome. The latter might share characteristics with a scanning SRP, complex, whereas the former represents the next step: the targeting, complex ready for receptor binding. High-resolution structures of the, bacterial ribosome and of the bacterial SRP components are available, and, their fitting explains our electron microscopic density. The structures, reveal the regions that are involved in complex formation, provide insight, into the conformation of the SRP on the ribosome and indicate the, conformational changes that accompany high-affinity SRP binding to, ribosome nascent chain complexes upon recognition of the signal sequence.
About this Structure
2IY3 is a Single protein structure of sequence from Thermus aquaticus. Full crystallographic information is available from OCA.
Reference
Structure of the E. coli signal recognition particle bound to a translating ribosome., Schaffitzel C, Oswald M, Berger I, Ishikawa T, Abrahams JP, Koerten HK, Koning RI, Ban N, Nature. 2006 Nov 23;444(7118):503-6. Epub 2006 Oct 29. PMID:17086205
Page seeded by OCA on Wed Nov 21 12:27:52 2007
