Light-activated DNA binding in a designed allosteric protein

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 105; no. 31; pp. 10709 - 10714
• Main Authors: Strickland, Devin, Moffat, Keith, Sosnick, Tobin R
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 05.08.2008; National Acad Sciences
• Subjects: 60 APPLIED LIFE SCIENCES; Adducts; Allosteric Site - genetics; Architecture; Avena - genetics; Avena sativa; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; BASIC BIOLOGICAL SCIENCES; Biochemistry; Biological Sciences; BIOLOGY; Cellular biology; Cryptochromes; Deoxyribonucleic acid; DESIGN; DIGESTION; DNA; DNA - genetics; DNA - metabolism; ESCHERICHIA COLI; Flavoproteins - genetics; Flavoproteins - metabolism; FUNCTIONALS; Genetic mutation; GEOMETRY; Light; Models, Molecular; NUCLEASES; Photoexcitation; Photons; Protein Binding; Protein engineering; Protein Engineering - methods; Protein Structure, Secondary - genetics; Protein Structure, Tertiary; PROTEINS; Repressor Proteins - genetics; Repressor Proteins - metabolism; Signaling proteins
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0709610105

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.