2HNF

Structure of a Hyper-cleavable Monomeric Fragment of Phage lambda Repressor Containing the Cleavage Site Region

Summary for 2HNF

• Entry DOI: 10.2210/pdb2hnf/pdb
• Related: 1F39 1JHC 1JHE 2HO0
• Descriptor: Repressor protein cI101-229DM-K192A, CALCIUM ION (3 entities in total)
• Functional Keywords: viral protein
• Biological source: Escherichia coli
• Total number of polymer chains: 1
• Total formula weight: 14760.75

Authors

Ndjonka, D.,Bell, C.E. (deposition date: 2006-07-12, release date: 2006-09-19, Last modification date: 2024-11-13)

Primary citation

Ndjonka, D.,Bell, C.E.
Structure of a Hyper-cleavable Monomeric Fragment of Phage lambda Repressor Containing the Cleavage Site Region.
J.Mol.Biol., 362:479-489, 2006

PubMed Abstract: The key event in the switch from lysogenic to lytic growth of phage lambda is the self-cleavage of lambda repressor, which is induced by the formation of a RecA-ssDNA-ATP filament at a site of DNA damage. Lambda repressor cleaves itself at the peptide bond between Ala111 and Gly112, but only when bound as a monomer to the RecA-ssDNA-ATP filament. Here we have designed a hyper-cleavable fragment of lambda repressor containing the hinge and C-terminal domain (residues 101-229), in which the monomer-monomer interface is disrupted by two point mutations and a deletion of seven residues at the C terminus. This fragment crystallizes as a monomer and its structure has been determined to 1.8 A resolution. The hinge region, which bears the cleavage site, is folded over the active site of the C-terminal oligomerization domain (CTD) but with the cleavage site flipped out and exposed to solvent. Thus, the structure represents a non-cleavable conformation of the repressor, but one that is poised for cleavage after modest rearrangements that are presumably stabilized by binding to RecA. The structure provides a unique snapshot of lambda repressor in a conformation that sheds light on how its self-cleavage is tempered in the absence of RecA, as well as a framework for interpreting previous genetic and biochemical data concerning the RecA-mediated cleavage reaction.

PubMed: 16934834
DOI: 10.1016/j.jmb.2006.07.026

Experimental method

X-RAY DIFFRACTION (1.8 Å)