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8gmu

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Structure of lambda repressor in complex with RecA filament

Structural highlights

8gmu is a 4 chain structure with sequence from Escherichia coli and Escherichia phage Lambda. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Electron Microscopy, Resolution 2.78Å
Ligands:	,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

RPC1_LAMBD Repressor protein CI allows phage lambda to reside inactively in the chromosome of its host bacterium. This lysogenic state is maintained by binding of regulatory protein CI to the OR and OL operators, preventing transcription of proteins necessary for lytic development.

Publication Abstract from PubMed

In response to DNA damage, bacterial RecA protein forms filaments with the assistance of DinI protein. The RecA filaments stimulate the autocleavage of LexA, the repressor of more than 50 SOS genes, and activate the SOS response. During the late phase of SOS response, the RecA filaments stimulate the autocleavage of UmuD and lambda repressor CI, leading to mutagenic repair and lytic cycle, respectively. Here, we determined the cryo-electron microscopy structures of Escherichia coli RecA filaments in complex with DinI, LexA, UmuD, and lambdaCI by helical reconstruction. The structures reveal that LexA and UmuD dimers bind in the filament groove and cleave in an intramolecular and an intermolecular manner, respectively, while lambdaCI binds deeply in the filament groove as a monomer. Despite their distinct folds and oligomeric states, all RecA filament binders recognize the same conserved protein features in the filament groove. The SOS response in bacteria can lead to mutagenesis and antimicrobial resistance, and our study paves the way for rational drug design targeting the bacterial SOS response.

Structural basis for regulation of SOS response in bacteria.,Gao B, Liang L, Su L, Wen A, Zhou C, Feng Y Proc Natl Acad Sci U S A. 2023 Jan 10;120(2):e2217493120. doi: , 10.1073/pnas.2217493120. Epub 2023 Jan 4. PMID:36598938^[1]

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

References

↑ Gao B, Liang L, Su L, Wen A, Zhou C, Feng Y. Structural basis for regulation of SOS response in bacteria. Proc Natl Acad Sci U S A. 2023 Jan 10;120(2):e2217493120. PMID:36598938 doi:10.1073/pnas.2217493120