3bdn
From Proteopedia
Crystal Structure of the Lambda Repressor
Structural highlights
FunctionRPC1_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. 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 PubMedBacteriophage lambda has for many years been a model system for understanding mechanisms of gene regulation. A 'genetic switch' enables the phage to transition from lysogenic growth to lytic development when triggered by specific environmental conditions. The key component of the switch is the cI repressor, which binds to two sets of three operator sites on the lambda chromosome that are separated by about 2,400 base pairs (bp). A hallmark of the lambda system is the pairwise cooperativity of repressor binding. In the absence of detailed structural information, it has been difficult to understand fully how repressor molecules establish the cooperativity complex. Here we present the X-ray crystal structure of the intact lambda cI repressor dimer bound to a DNA operator site. The structure of the repressor, determined by multiple isomorphous replacement methods, reveals an unusual overall architecture that allows it to adopt a conformation that appears to facilitate pairwise cooperative binding to adjacent operator sites. Crystal structure of the lambda repressor and a model for pairwise cooperative operator binding.,Stayrook S, Jaru-Ampornpan P, Ni J, Hochschild A, Lewis M Nature. 2008 Apr 24;452(7190):1022-5. PMID:18432246[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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