2ho0
From Proteopedia
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Structure of a Hyper-cleavable Monomeric Fragment of Phage Lambda Repressor Containing the Cleavage Site Region
Overview
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.
About this Structure
2HO0 is a Single protein structure of sequence from Escherichia coli with as ligand. Full crystallographic information is available from OCA.
Reference
Structure of a hyper-cleavable monomeric fragment of phage lambda repressor containing the cleavage site region., Ndjonka D, Bell CE, J Mol Biol. 2006 Sep 22;362(3):479-89. Epub 2006 Jul 15. PMID:16934834
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