Xueqi Huo, Zijie Zhou, Hongliang Liu, Gejiao Wang, Kaixiang Shi
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引用次数: 0
Abstract
Chromium is a prevalent toxic heavy metal, and chromate [Cr(VI)] exhibits high mutagenicity and carcinogenicity. The presence of the Cr(VI) efflux protein ChrA has been identified in strains exhibiting resistance to Cr(VI). Nevertheless, certain strains of bacteria that are resistant to Cr(VI) lack the presence of ChrB, a known regulatory factor. Here, a PadR family transcriptional repressor, ChrN, has been identified as a regulator in the response of Enterobacter sp. Z1(CCTCC NO: M 2019147) to Cr(VI). The chrN gene is cotranscribed with the chrA gene, and the transcriptional expression of this operon is induced by Cr(VI). The binding capacity of the ChrN protein to Cr(VI) was demonstrated by both the tryptophan fluorescence assay and Ni-NTA purification assay. The interaction between ChrN and the chrAN operon promoter was validated by reporter gene assay and electrophoretic mobility shift assay. Mutation of the conserved histidine residues His14 and His50 resulted in loss of ChrN binding with the promoter of the chrAN operon. This observation implies that these residues are crucial for establishing a DNA-binding site. These findings demonstrate that ChrN functions as a transcriptional repressor, modulating the cellular response of strain Z1 to Cr(VI) exposure.
期刊介绍:
Publishes papers that deal with research on microorganisms, including archaea, bacteria, yeasts, fungi, microalgae, protozoa, and simple eukaryotic microorganisms. Topics considered for publication include Microbial Systematics, Evolutionary Microbiology, Microbial Ecology, Environmental Microbiology, Microbial Genetics, Genomics, Molecular Biology, Microbial Physiology, Biochemistry, Microbial Pathogenesis, Host-Microbe Interaction, Systems Microbiology, Synthetic Microbiology, Bioinformatics and Virology. Manuscripts dealing with simple identification of microorganism(s), cloning of a known gene and its expression in a microbial host, and clinical statistics will not be considered for publication by JM.