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Updated: Sep 28, 2026

Using Mycobacterium smegmatis as a Bioindicator for Zinc-Limited Growth Conditions in Mycobacteria
Published on: September 20, 2024
Zinc ions inhibit the protein-DNA complex formation between cyanobacterial transcription factor SmtB and its
Eugene Hayato Morita1, Miki Wakamatsu, Koichi Uegaki
1Department of Chemistry, Faculty of Science, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime, 790-8577 Japan. ehmorita@dpc.ehime-u.ac.jp
Abstract:
SmtB is a trans-acting dimeric repressor of the metal-regulated smtA gene, and the release of SmtB from the smtA operator/promoter region is essential for the tolerance to Zn(2+) stress by SmtA expression. Gel retardation assaying demonstrated that different sizes of SmtB-DNA complexes were formed depending on the DNA sequences, and the amounts of these complexes decreased in the presence of Zn(2+). Here, we present the first direct evidence that Zn(2+ )(>4 micro M) inhibits the SmtB-DNA complex formation in vitro, which ensures the physiological functions of SmtB as a Zn(2+) sensor and a transcription factor.
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