title: Direct observation of TALE protein dynamics reveals a two-state search mechanism.
abstract: Transcription activator-like effector (TALE) proteins are a class of programmable DNA-binding proteins for which the fundamental mechanisms governing the search process are not fully understood. Here we use single-molecule techniques to directly observe TALE search dynamics along DNA templates. We find that TALE proteins are capable of rapid diffusion along DNA using a combination of sliding and hopping behaviour, which suggests that the TALE search process is governed in part by facilitated diffusion. We also observe that TALE proteins exhibit two distinct modes of action during the search process-a search state and a recognition state-facilitated by different subdomains in monomeric TALE proteins. Using TALE truncation mutants, we further demonstrate that the N-terminal region of TALEs is required for the initial non-specific binding and subsequent rapid search along DNA, whereas the central repeat domain is required for transitioning into the site-specific recognition state.
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Luke
authors.initials: L
authors.lastname: Cuculis
authors.affiliation: Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Zhanar
authors.initials: Z
authors.lastname: Abil
authors.affiliation: 1] Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA [2] Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA [3] Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA [4] Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801 USA [5] Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Huimin
authors.initials: H
authors.lastname: Zhao
authors.affiliation: 1] Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA [2] Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA [3] Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801 USA [4] Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Charles M
authors.initials: CM
authors.lastname: Schroeder
mesh_terms: D001665:Binding Sites; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004058:Diffusion; D004926:Escherichia coli; D005454:Fluorescence Polarization; D008856:Microscopy, Fluorescence; D011485:Protein Binding; D013302:Streptomyces; D015533:Transcriptional Activation
chemical_list: D004268:DNA-Binding Proteins; D004247:DNA