7o5b

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Cryo-EM structure of a Bacillus subtilis MifM-stalled ribosome-nascent chain complex with (p)ppGpp-SRP bound

Structural highlights

7o5b is a 10 chain structure with sequence from Bacillus subtilis subsp. subtilis str. 168. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:Electron Microscopy, Resolution 3.33Å
Ligands:G4P
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

SRP54_BACSU Involved in targeting and insertion of nascent membrane proteins into the cytoplasmic membrane. Binds to the hydrophobic signal sequence of the ribosome-nascent chain (RNC) as it emerges from the ribosomes. The SRP-RNC complex is then targeted to the cytoplasmic membrane where it interacts with the SRP receptor FtsY. Interaction with FtsY leads to the transfer of the RNC complex to the Sec translocase for insertion into the membrane, the hydrolysis of GTP by both Ffh and FtsY, and the dissociation of the SRP-FtsY complex into the individual components (Probable).[1]

Publication Abstract from PubMed

The stringent response enables bacteria to respond to nutrient limitation and other stress conditions through production of the nucleotide-based second messengers ppGpp and pppGpp, collectively known as (p)ppGpp. Here, we report that (p)ppGpp inhibits the signal recognition particle (SRP)-dependent protein targeting pathway, which is essential for membrane protein biogenesis and protein secretion. More specifically, (p)ppGpp binds to the SRP GTPases Ffh and FtsY, and inhibits the formation of the SRP receptor-targeting complex, which is central for the coordinated binding of the translating ribosome to the SecYEG translocon. Cryo-EM analysis of SRP bound to translating ribosomes suggests that (p)ppGpp may induce a distinct conformational stabilization of the NG domain of Ffh and FtsY in Bacillus subtilis but not in E. coli.

Inhibition of SRP-dependent protein secretion by the bacterial alarmone (p)ppGpp.,Czech L, Mais CN, Kratzat H, Sarmah P, Giammarinaro P, Freibert SA, Esser HF, Musial J, Berninghausen O, Steinchen W, Beckmann R, Koch HG, Bange G Nat Commun. 2022 Feb 25;13(1):1069. doi: 10.1038/s41467-022-28675-0. PMID:35217658[2]

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

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See Also

References

  1. Nakamura K, Nishiguchi M, Honda K, Yamane K. The Bacillus subtilis SRP54 homologue, Ffh, has an intrinsic GTPase activity and forms a ribonucleoprotein complex with small cytoplasmic RNA in vivo. Biochem Biophys Res Commun. 1994 Mar 30;199(3):1394-9. PMID:7511896 doi:http://dx.doi.org/10.1006/bbrc.1994.1385
  2. Czech L, Mais CN, Kratzat H, Sarmah P, Giammarinaro P, Freibert SA, Esser HF, Musial J, Berninghausen O, Steinchen W, Beckmann R, Koch HG, Bange G. Inhibition of SRP-dependent protein secretion by the bacterial alarmone (p)ppGpp. Nat Commun. 2022 Feb 25;13(1):1069. doi: 10.1038/s41467-022-28675-0. PMID:35217658 doi:http://dx.doi.org/10.1038/s41467-022-28675-0

Contents


PDB ID 7o5b

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