Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe 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. 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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