Light-activated DNA binding in a designed allosteric protein
- Department of Biochemistry and Molecular Biology and Institute for Biophysical Dynamics, University of Chicago, 929 East 57th Street, Chicago, IL 60637
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Edited by David Baker, University of Washington, Seattle, WA, and approved May 12, 2008 (received for review October 9, 2007)
Abstract
An understanding of how allostery, the conformational coupling of distant functional sites, arises in highly evolvable systems is of considerable interest in areas ranging from cell biology to protein design and signaling networks. We reasoned that the rigidity and defined geometry of an α-helical domain linker would make it effective as a conduit for allosteric signals. To test this idea, we rationally designed 12 fusions between the naturally photoactive LOV2 domain from Avena sativa phototropin 1 and the Escherichia coli trp repressor. When illuminated, one of the fusions selectively binds operator DNA and protects it from nuclease digestion. The ready success of our rational design strategy suggests that the helical “allosteric lever arm” is a general scheme for coupling the function of two proteins.
Footnotes
- *To whom correspondence should be addressed at: Department of Biochemistry and Molecular Biology, University of Chicago, 929 E. 57th Street, GCIS W101C, Chicago, IL 60637. E-mail: trsosnic{at}uchicago.edu
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Author contributions: D.S., K.M., and T.R.S. designed research; D.S. performed research; D.S., K.M., and T.R.S. analyzed data; and D.S., K.M., and T.R.S. wrote the paper.
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A patent application relating to this work has been filed for which D.S., K.M., and T.R.S. are coinventors.
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This article is a PNAS Direct Submission.
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This article contains supporting information online at www.pnas.org/cgi/content/full/0709610105/DCSupplemental.
- © 2008 by The National Academy of Sciences of the USA
