title: A structural approach reveals how neighbouring C2H2 zinc fingers influence DNA binding specificity.
abstract: Development of an accurate protein-DNA recognition code that can predict DNA specificity from protein sequence is a central problem in biology. C2H2 zinc fingers constitute by far the largest family of DNA binding domains and their binding specificity has been studied intensively. However, despite decades of research, accurate prediction of DNA specificity remains elusive. A major obstacle is thought to be the inability of current methods to account for the influence of neighbouring domains. Here we show that this problem can be addressed using a structural approach: we build structural models for all C2H2-ZF-DNA complexes with known binding motifs and find six distinct binding modes. Each mode changes the orientation of specificity residues with respect to the DNA, thereby modulating base preference. Most importantly, the structural analysis shows that residues at the domain interface strongly and predictably influence the binding mode, and hence specificity. Accounting for predicted binding mode significantly improves prediction accuracy of predicted motifs. This new insight into the fundamental behaviour of C2H2-ZFs has implications for both improving the prediction of natural zinc finger-binding sites, and for prioritizing further experiments to complete the code. It also provides a new design feature for zinc finger engineering.
authors.affiliation: Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto M5S 3E1, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Garton
authors.affiliation: Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto M5S 3E1, Canada.
authors.forename: Hamed S
authors.initials: HS
authors.lastname: Najafabadi
authors.affiliation: Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto M5S 3E1, Canada.
authors.forename: Frank W
authors.initials: FW
authors.lastname: Schmitges
authors.affiliation: Department of Molecular Genetics, University of Toronto, Toronto M5S 1A8, Canada.
authors.forename: Ernest
authors.initials: E
authors.lastname: Radovani
authors.affiliation: Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto M5S 3E1, Canada Department of Molecular Genetics, University of Toronto, Toronto M5S 1A8, Canada.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Hughes
authors.affiliation: Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto M5S 3E1, Canada Department of Molecular Genetics, University of Toronto, Toronto M5S 1A8, Canada Department of Computer Science, University of Toronto, Toronto M5S 2E4, Canada pi@kimlab.org.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Kim
mesh_terms: D001665:Binding Sites; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D030562:Databases, Protein; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D020539:Sequence Analysis, Protein; D016335:Zinc Fingers
chemical_list: D004268:DNA-Binding Proteins; D004247:DNA