Structural basis for sequence-specific recognition of DNA by TAL effectors.

TitleStructural basis for sequence-specific recognition of DNA by TAL effectors.
Publication TypeJournal Article
Year of Publication2012
AuthorsDeng, D, Yan, C, Pan, X, Mahfouz, M, Wang, J, Zhu, J-K, Shi, Y, Yan, N
Date Published2012 Feb 10
KeywordsAmino Acid Sequence, Bacterial Proteins, Base Sequence, Chemical Phenomena, Crystallography, X-Ray, DNA, DNA-Binding Proteins, Hydrogen Bonding, Models, Molecular, Molecular Sequence Data, Protein Conformation, Protein Structure, Secondary, Protein Structure, Tertiary, Repetitive Sequences, Amino Acid, Virulence Factors, Xanthomonas

TAL (transcription activator-like) effectors, secreted by phytopathogenic bacteria, recognize host DNA sequences through a central domain of tandem repeats. Each repeat comprises 33 to 35 conserved amino acids and targets a specific base pair by using two hypervariable residues [known as repeat variable diresidues (RVDs)] at positions 12 and 13. Here, we report the crystal structures of an 11.5-repeat TAL effector in both DNA-free and DNA-bound states. Each TAL repeat comprises two helices connected by a short RVD-containing loop. The 11.5 repeats form a right-handed, superhelical structure that tracks along the sense strand of DNA duplex, with RVDs contacting the major groove. The 12th residue stabilizes the RVD loop, whereas the 13th residue makes a base-specific contact. Understanding DNA recognition by TAL effectors may facilitate rational design of DNA-binding proteins with biotechnological applications.

Alternate JournalScience
PubMed ID22223738
PubMed Central IDPMC3586824
Grant ListR01 GM070795 / GM / NIGMS NIH HHS / United States