Summary information and primary citation
- PDB-id
- 6chv; SNAP-derived features in text and JSON formats;
DNAproDB
- Class
- antitoxin-DNA
- Method
- X-ray (2.9 Å)
- Summary
- Proteus vulgaris higa antitoxin bound to DNA
- Reference
- Schureck MA, Meisner J, Hoffer ED, Wang D, Onuoha N, Ei Cho S, Lollar 3rd P, Dunham CM (2019): "Structural basis of transcriptional regulation by the HigA antitoxin." Mol.Microbiol., 111, 1449-1462. doi: 10.1111/mmi.14229.
- Abstract
- Bacterial toxin-antitoxin systems are important factors implicated in growth inhibition and plasmid maintenance. Type II toxin-antitoxin pairs are regulated at the transcriptional level by the antitoxin itself. Here, we examined how the HigA antitoxin regulates the expression of the Proteus vulgaris higBA toxin-antitoxin operon from the Rts1 plasmid. The HigBA complex adopts a unique architecture suggesting differences in its regulation as compared to classical type II toxin-antitoxin systems. We find that the C-terminus of the HigA antitoxin is required for dimerization and transcriptional repression. Further, the HigA structure reveals that the C terminus is ordered and does not transition between disorder-order states upon toxin binding. HigA residue Arg40 recognizes a TpG dinucleotide in higO2, an evolutionary conserved mode of recognition among prokaryotic and eukaryotic transcriptional factors. Comparison of the HigBA and HigA-higO2 structures reveals the distance between helix-turn-helix motifs of each HigA monomer increases by ~4 Å in order to bind to higO2. Consistent with these data, HigBA binding to each operator is two-fold less tight than HigA alone. Together, these data show the HigB toxin does not act as a co-repressor suggesting potential novel regulation in this toxin-antitoxin system. This article is protected by copyright. All rights reserved.