Zinc ions inhibit the protein-DNA complex formation between cyanobacterial transcription factor SmtB and its recognition DNA sequences.
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.
Morita
Eugene Hayato
EH
Department of Chemistry, Faculty of Science, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime, 790-8577 Japan. ehmorita@dpc.ehime-u.ac.jp
Wakamatsu
Miki
M
Uegaki
Koichi
K
Yumoto
Noboru
N
Kyogoku
Yoshimasa
Y
Hayashi
Hidenori
H
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D000458:Cyanobacteria / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000187:drug effects; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015032:Zinc / Q000494:pharmacology*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D015032:Zinc