title: A photoswitchable DNA-binding protein based on a truncated GCN4-photoactive yellow protein chimera.
abstract: Photo-controlled DNA-binding proteins promise to be useful tools for probing complex spatiotemporal patterns of gene expression in living organisms. Here we report a novel photoswitchable DNA-binding protein, GCN4(S)Δ25PYP, based on a truncated GCN4-photoactive yellow protein chimera. In contrast to previously reported designed photoswitchable proteins where DNA binding affinity is enhanced upon irradiation, GCN4(S)Δ25PYP dissociates from DNA when irradiated with blue light. In addition, the rate of thermal relaxation to the ground state, part of the PYP photocycle, is enhanced by DNA binding whereas in previous reported constructs it is slowed. The origins of this reversed photoactivity are analyzed in structural terms.
authors.affiliation: Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON M5S 3H6, Canada.
authors.forename: Stacy-Anne
authors.initials: SA
authors.lastname: Morgan
authors.forename: G Andrew
authors.initials: GA
authors.lastname: Woolley
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D050976:Basic-Leucine Zipper Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008027:Light; D008969:Molecular Sequence Data; D020283:Photoreceptors, Microbial / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry* / Q000378:metabolism / Q000528:radiation effects; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet
chemical_list: D001426:Bacterial Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; C501391:GCN4 protein, S cerevisiae; D020283:Photoreceptors, Microbial; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; C050162:photoactive yellow protein, Bacteria; D004247:DNA