4HF0

Crystal Structure of Apo IscR

4HF0 の概要

• エントリーDOI: 10.2210/pdb4hf0/pdb
• 関連するPDBエントリー: 4HF1 4HF2
• 分子名称: HTH-type transcriptional regulator IscR, SULFATE ION (3 entities in total)
• 機能のキーワード: whth, protein-dna complex, iron-sulfur cluster, winged helix-turn-helix, transcriptional regulator, redox sensor, dna binding, transcription
• 由来する生物種: Escherichia coli
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 29957.48

構造登録者

Rajagopalan, S.R.,Phillips, K.J. (登録日: 2012-10-04, 公開日: 2013-05-08, 最終更新日: 2024-02-28)

主引用文献

Rajagopalan, S.,Teter, S.J.,Zwart, P.H.,Brennan, R.G.,Phillips, K.J.,Kiley, P.J.
Studies of IscR reveal a unique mechanism for metal-dependent regulation of DNA binding specificity.
Nat.Struct.Mol.Biol., 20:740-747, 2013

PubMed Abstract: IscR from Escherichia coli is an unusual metalloregulator in that both apo and iron sulfur (Fe-S)-IscR regulate transcription and exhibit different DNA binding specificities. Here, we report structural and biochemical studies of IscR suggesting that remodeling of the protein-DNA interface upon Fe-S ligation broadens the DNA binding specificity of IscR from binding the type 2 motif only to both type 1 and type 2 motifs. Analysis of an apo-IscR variant with relaxed target-site discrimination identified a key residue in wild-type apo-IscR that, we propose, makes unfavorable interactions with a type 1 motif. Upon Fe-S binding, these interactions are apparently removed, thereby allowing holo-IscR to bind both type 1 and type 2 motifs. These data suggest a unique mechanism of ligand-mediated DNA site recognition, whereby metallocluster ligation relocates a protein-specificity determinant to expand DNA target-site selection, allowing a broader transcriptomic response by holo-IscR.

PubMed: 23644595
DOI: 10.1038/nsmb.2568

実験手法

X-RAY DIFFRACTION (1.9 Å)