Tandem DNA Recognition by PhoB, a Two-Component Signal Transduction Transcriptional Activator

• Published in: Structure (London) 2002-05, Vol.10 (5), p.701-713
• Main Authors: Blanco, Alexandre G., Sola, Maria, Gomis-Rüth, F.Xavier, Coll, Miquel
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; crystal structure; DNA - metabolism; DNA binding domain; DNA-Binding Proteins - chemistry; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Escherichia coli - chemistry; Escherichia coli - metabolism; Escherichia coli Proteins - chemistry; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Models, Molecular; Molecular Sequence Data; Nucleic Acid Conformation; PhoB; Promoter Regions, Genetic; Protein Binding; Protein Structure, Tertiary; Sequence Alignment; Signal Transduction - physiology; tandem protein-DNA complex; Trans-Activators - chemistry; Trans-Activators - genetics; Trans-Activators - metabolism; two-component signal transduction
• ISSN: 0969-2126; 1878-4186
• DOI: 10.1016/S0969-2126(02)00761-X

PhoB is a signal transduction response regulator that activates nearly 40 genes in phosphate depletion conditions in E. coli and closely related bacteria. The structure of the PhoB effector domain in complex with its target DNA sequence, or pho box, reveals a novel tandem arrangement in which several monomers bind head to tail to successive 11-base pair direct-repeat sequences, coating one face of a smoothly bent double helix. The protein has a winged helix fold in which the DNA recognition elements comprise helix α3, penetrating the major groove, and a β hairpin wing interacting with a compressed minor groove via Arg219, tightly sandwiched between the DNA sugar backbones. The transactivation loops protrude laterally in an appropriate orientation to interact with the RNA polymerase σ 70 subunit, which triggers transcription initiation.