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Updated: Aug 23, 2026

From Constructs to Crystals – Towards Structure Determination of β-barrel Outer Membrane Proteins
Published on: July 4, 2016
The solution structure of ChaB, a putative membrane ion antiporter regulator from Escherichia coli
Michael J Osborne1, Nadeem Siddiqui, Pietro Iannuzzi
1Department of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada, H3G 1Y6. mike@bri.nrc.ca
Background:
ChaB is a putative regulator of ChaA, a Na+/H+ antiporter that also has Ca+/H+ activity in E. coli. ChaB contains a conserved 60-residue region of unknown function found in other bacteria, archaeabacteria and a series of baculoviral proteins. As part of a structural genomics project, the structure of ChaB was elucidated by NMR spectroscopy.
Results:
The structure of ChaB is composed of 3 alpha-helices and a small sheet that pack tightly to form a fold that is found in the cyclin-box family of proteins.
Conclusion:
ChaB is distinguished from its putative DNA binding sequence homologues by a highly charged flexible loop region that has weak affinity to Mg2+ and Ca2+ divalent metal ions.
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