7obq

SRP-SR at the distal site conformationSRP-SR at the distal site conformation

Structural highlights

7obq is a 8 chain structure with sequence from Canis lupus familiaris, Oryctolagus cuniculus and Saccharomyces cerevisiae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Electron Microscopy, Resolution 3.9Å
Ligands:	, ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

SRP19_CANLF Component of the signal recognition particle (SRP) complex, a ribonucleoprotein complex that mediates the cotranslational targeting of secretory and membrane proteins to the endoplasmic reticulum (ER) (PubMed:6413076, PubMed:6938958). Binds directly to 7SL RNA (PubMed:6413076). Mediates binding of SRP54 to the SRP complex (PubMed:6413076).^[1] ^[2]

Publication Abstract from PubMed

Co-translational protein targeting to membranes by the signal recognition particle (SRP) is a universally conserved pathway from bacteria to humans. In mammals, SRP and its receptor (SR) have many additional RNA features and protein components compared to the bacterial system, which were recently shown to play regulatory roles. Due to its complexity, the mammalian SRP targeting process is mechanistically not well understood. In particular, it is not clear how SRP recognizes translating ribosomes with exposed signal sequences and how the GTPase activity of SRP and SR is regulated. Here, we present electron cryo-microscopy structures of SRP and SRP.SR in complex with the translating ribosome. The structures reveal the specific molecular interactions between SRP and the emerging signal sequence and the elements that regulate GTPase activity of SRP.SR. Our results suggest the molecular mechanism of how eukaryote-specific elements regulate the early and late stages of SRP-dependent protein targeting.

Molecular mechanism of cargo recognition and handover by the mammalian signal recognition particle.,Jomaa A, Eitzinger S, Zhu Z, Chandrasekar S, Kobayashi K, Shan SO, Ban N Cell Rep. 2021 Jul 13;36(2):109350. doi: 10.1016/j.celrep.2021.109350. PMID:34260909^[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Walter P, Blobel G. Disassembly and reconstitution of signal recognition particle. Cell. 1983 Sep;34(2):525-33. PMID:6413076 doi:10.1016/0092-8674(83)90385-9
↑ Walter P, Blobel G. Purification of a membrane-associated protein complex required for protein translocation across the endoplasmic reticulum. Proc Natl Acad Sci U S A. 1980 Dec;77(12):7112-6. PMID:6938958 doi:10.1073/pnas.77.12.7112
↑ Jomaa A, Eitzinger S, Zhu Z, Chandrasekar S, Kobayashi K, Shan SO, Ban N. Molecular mechanism of cargo recognition and handover by the mammalian signal recognition particle. Cell Rep. 2021 Jul 13;36(2):109350. PMID:34260909 doi:10.1016/j.celrep.2021.109350

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OCA

[1] Walter P, Blobel G. Disassembly and reconstitution of signal recognition particle. Cell. 1983 Sep;34(2):525-33. PMID:6413076 doi:10.1016/0092-8674(83)90385-9

[2] Walter P, Blobel G. Purification of a membrane-associated protein complex required for protein translocation across the endoplasmic reticulum. Proc Natl Acad Sci U S A. 1980 Dec;77(12):7112-6. PMID:6938958 doi:10.1073/pnas.77.12.7112

[3] Jomaa A, Eitzinger S, Zhu Z, Chandrasekar S, Kobayashi K, Shan SO, Ban N. Molecular mechanism of cargo recognition and handover by the mammalian signal recognition particle. Cell Rep. 2021 Jul 13;36(2):109350. PMID:34260909 doi:10.1016/j.celrep.2021.109350

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