6G26

The crystal structure of the Burkholderia pseudomallei HicAB complex

6G26 の概要

• エントリーDOI: 10.2210/pdb6g26/pdb
• 分子名称: HicB, HicA, SULFATE ION, ... (6 entities in total)
• 機能のキーワード: n-terminal domain of the antitoxin hicb which acts as an inhibitor to hica, antitoxin
• 由来する生物種: Burkholderia pseudomallei K96243; 詳細
• タンパク質・核酸の鎖数: 8
• 化学式量合計: 93067.76

構造登録者

Winter, A.J.,Isupov, M.N.,Williams, C.,Crump, M.P. (登録日: 2018-03-22, 公開日: 2018-10-31, 最終更新日: 2024-01-17)

主引用文献

Winter, A.J.,Williams, C.,Isupov, M.N.,Crocker, H.,Gromova, M.,Marsh, P.,Wilkinson, O.J.,Dillingham, M.S.,Harmer, N.J.,Titball, R.W.,Crump, M.P.
The molecular basis of protein toxin HicA-dependent binding of the protein antitoxin HicB to DNA.
J. Biol. Chem., 293:19429-19440, 2018

PubMed Abstract: Toxin-antitoxin (TA) systems are present in many bacteria and play important roles in bacterial growth, physiology, and pathogenicity. Those that are best studied are the type II TA systems, in which both toxins and antitoxins are proteins. The HicAB system is one of the prototypic TA systems, found in many bacterial species. Complex interactions between the protein toxin (HicA), the protein antitoxin (HicB), and the DNA upstream of the encoding genes regulate the activity of this system, but few structural details are available about how HicA destabilizes the HicB-DNA complex. Here, we determined the X-ray structures of HicB and the HicAB complex to 1.8 and 2.5 Å resolution, respectively, and characterized their DNA interactions. This revealed that HicB forms a tetramer and HicA and HicB form a heterooctameric complex that involves structural reorganization of the C-terminal (DNA-binding) region of HicB. Our observations indicated that HicA has a profound impact on binding of HicB to DNA sequences upstream of in a stoichiometric-dependent way. At low ratios of HicA:HicB, there was no effect on DNA binding, but at higher ratios, the affinity for DNA declined cooperatively, driving dissociation of the HicA:HicB:DNA complex. These results reveal the structural mechanisms by which HicA de-represses the HicB-DNA complex.

PubMed: 30337369
DOI: 10.1074/jbc.RA118.005173

実験手法

X-RAY DIFFRACTION (2.49 Å)