1. The crystal structure of TAL effector PthXo1 bound to its DNA target.
- Author
-
Mak AN, Bradley P, Cernadas RA, Bogdanove AJ, and Stoddard BL
- Subjects
- Amino Acid Sequence, Binding Sites, Chemical Phenomena, Crystallography, X-Ray, DNA-Binding Proteins chemistry, DNA-Binding Proteins metabolism, High-Throughput Screening Assays, Hydrogen Bonding, Models, Molecular, Molecular Sequence Data, Protein Binding, Protein Conformation, Protein Folding, Protein Structure, Secondary, Repetitive Sequences, Amino Acid, Xanthomonas pathogenicity, Bacterial Proteins chemistry, Bacterial Proteins metabolism, DNA, Plant chemistry, DNA, Plant metabolism, Virulence Factors chemistry, Virulence Factors metabolism, Xanthomonas chemistry
- Abstract
DNA recognition by TAL effectors is mediated by tandem repeats, each 33 to 35 residues in length, that specify nucleotides via unique repeat-variable diresidues (RVDs). The crystal structure of PthXo1 bound to its DNA target was determined by high-throughput computational structure prediction and validated by heavy-atom derivatization. Each repeat forms a left-handed, two-helix bundle that presents an RVD-containing loop to the DNA. The repeats self-associate to form a right-handed superhelix wrapped around the DNA major groove. The first RVD residue forms a stabilizing contact with the protein backbone, while the second makes a base-specific contact to the DNA sense strand. Two degenerate amino-terminal repeats also interact with the DNA. Containing several RVDs and noncanonical associations, the structure illustrates the basis of TAL effector-DNA recognition.
- Published
- 2012
- Full Text
- View/download PDF