The crystal structure of TAL effector PthXo1 bound to its DNA target.
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.
Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, A3-025 Seattle, WA 98019, USA.
Amanda Nga-Sze
AN
Mak
Philip
P
Bradley
Raul A
RA
Cernadas
Adam J
AJ
Bogdanove
Barry L
BL
Stoddard
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D001665:Binding Sites; D055598:Chemical Phenomena; D018360:Crystallography, X-Ray; D018744:DNA, Plant / Q000737:chemistry* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D057166:High-Throughput Screening Assays; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D020449:Repetitive Sequences, Amino Acid; D037521:Virulence Factors / Q000737:chemistry* / Q000378:metabolism*; D014974:Xanthomonas / Q000737:chemistry* / Q000472:pathogenicity
D001426:Bacterial Proteins; D018744:DNA, Plant; D004268:DNA-Binding Proteins; D037521:Virulence Factors