5IFG

Crystal structure of HigA-HigB complex from E. Coli

Summary for 5IFG

• Entry DOI: 10.2210/pdb5ifg/pdb
• Descriptor: mRNA interferase HigB, Antitoxin HigA (2 entities in total)
• Functional Keywords: mrna interferase, hydrolase-antitoxin complex, hydrolase/antitoxin
• Biological source: Escherichia coli (strain K12); More
• Total number of polymer chains: 4
• Total formula weight: 55019.30

Authors

Yang, J.S.,Zhou, K.,Gao, z.Q.,Liu, Q.S.,Dong, Y.H. (deposition date: 2016-02-26, release date: 2017-03-01, Last modification date: 2024-10-16)

Primary citation

Yang, J.,Zhou, K.,Liu, P.,Dong, Y.,Gao, Z.,Zhang, J.,Liu, Q.
Structural insight into the E. coli HigBA complex
Biochem. Biophys. Res. Commun., 478:1521-1527, 2016

PubMed Abstract: The toxin-antitoxin system is ubiquitously existed in bacteria and archaea, performing a wide variety of functions modulating cell fitness in response to environmental cues. In this report, we solved the crystal structure of the toxin-antitoxin HigBA complex from E. coli K-12 to 2.7 Å resolution. The crystal structure of the HigBA complex displays a hetero-tetramer (HigBA)2 form comprised by two HigB and two HigA subunits. Each toxin HigB resumes a microbial RNase T1 fold, characteristic of a three antiparallel β-sheet core shielded by a few α-helices at either side. Each antitoxin HigA composed of all α-helices resembles a "C"-shaped clamp nicely encompassing a HigB in the (HigBA)2 complex. Two HigA monomers dimerize at their N-terminal domain. We showed that HigA helix α1 was essential for HigA dimerization and the hetero-tetramer (HigBA)2 formation, but not for a hetero-dimeric HigBA formation. HigA dimerization mediated by helix α1 was dispensable for DNA-binding, as a heterodimeric HigBA complex still bound to the higBA operator in vitro. The HigA C-terminal domain with a helix-turn-helix fold was essential for DNA binding. We also defined two palindromes in higBA operator specifically recognized by HigA and HigBA in vitro.

PubMed: 27601326
DOI: 10.1016/j.bbrc.2016.08.131

Experimental method

X-RAY DIFFRACTION (2.702 Å)