The E. coli HicB Antitoxin Contains a Structurally Stable Helix-Turn-Helix DNA Binding Domain.
Structure
; 27(11): 1675-1685.e3, 2019 11 05.
Article
in En
| MEDLINE
| ID: mdl-31495532
ABSTRACT
The E. coli hicAB type II toxin-antitoxin locus is unusual by being controlled by two promoters and by having the toxin encoded upstream of the antitoxin. HicA toxins contain a double-stranded RNA-binding fold and cleaves both mRNA and tmRNA in vivo, while HicB antitoxins contain a partial RNase H fold and either a helix-turn-helix (HTH) or ribbon-helix-helix domain. It is not known how an HTH DNA-binding domain affects higher-order structure for the HicAB modules. Here, we present crystal structures of the isolated E. coli HicB antitoxin and full-length HicAB complex showing that HicB forms a stable DNA-binding module and interacts in a canonical way with HicA despite the presence of an HTH-type DNA-binding domain. No major structural rearrangements take place upon binding of the toxin. Both structures expose well-ordered DNA-binding motifs allowing a model for DNA binding by the antitoxin to be generated.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Escherichia coli Proteins
/
DNA-Binding Proteins
/
Toxin-Antitoxin Systems
Language:
En
Journal:
Structure
Journal subject:
BIOLOGIA MOLECULAR
/
BIOQUIMICA
/
BIOTECNOLOGIA
Year:
2019
Document type:
Article
Affiliation country:
Denmark