In the archaeon Sulfolobus solfataricus a DNA binding protein, Bald16 (Sso1352), has been identified whose levels are higher when cells are grown in the presence of the toxic benzaldehyde, substrate of the Sso2536ADH enzyme; it has been proposed that this protein could act as a transcriptional activator triggering adh expression to protect cells from an environmental stress due to phenolic-derived aldehydes. Bald16 has a bacterial homologue belonging to the Mar (Multiple Antibiotic Resistance) family of regulators involved in the control of gene expression of aromatic compound metabolism and antibiotic resistance. The gene encoding for the transcriptional regulator, has been expressed in E. coli and the recombinant protein purified to homogeneity. The protein is indeed a dimeric DNA binding protein, which binds site-specifically to both the adh and bald16 promoters; it also specifically interacts with benzaldehyde, as revealed by CD spectra analysis. In S.solfataricus, Bald16 is co-transcribed with an upstream gene (Sso1352) encoding a putative multidrug transporter (Mar-like operon). Northern blot analysis revealed that the operon might be autoregulated when cells are grown in the presence of aromatic aldehydes. Western blot analysis also revealed an increased Bald16 expression in cell extracts prepared from the same cells. These results reasonably strengthen the hypothesis of a resistance mechanism, modulated by Bald16, based on the coordinate expression of the adhgene and the Mar-like operon, in response to stress determined by phenolic-derived materials.

Bald16, a Mar-like transcriptional regulator is involved in the detoxification of aromatic compounds in Sulfolobus solfataricus.

FIORENTINO, GABRIELLA;RONCA, RAFFAELE;BARTOLUCCI, SIMONETTA
2005

Abstract

In the archaeon Sulfolobus solfataricus a DNA binding protein, Bald16 (Sso1352), has been identified whose levels are higher when cells are grown in the presence of the toxic benzaldehyde, substrate of the Sso2536ADH enzyme; it has been proposed that this protein could act as a transcriptional activator triggering adh expression to protect cells from an environmental stress due to phenolic-derived aldehydes. Bald16 has a bacterial homologue belonging to the Mar (Multiple Antibiotic Resistance) family of regulators involved in the control of gene expression of aromatic compound metabolism and antibiotic resistance. The gene encoding for the transcriptional regulator, has been expressed in E. coli and the recombinant protein purified to homogeneity. The protein is indeed a dimeric DNA binding protein, which binds site-specifically to both the adh and bald16 promoters; it also specifically interacts with benzaldehyde, as revealed by CD spectra analysis. In S.solfataricus, Bald16 is co-transcribed with an upstream gene (Sso1352) encoding a putative multidrug transporter (Mar-like operon). Northern blot analysis revealed that the operon might be autoregulated when cells are grown in the presence of aromatic aldehydes. Western blot analysis also revealed an increased Bald16 expression in cell extracts prepared from the same cells. These results reasonably strengthen the hypothesis of a resistance mechanism, modulated by Bald16, based on the coordinate expression of the adhgene and the Mar-like operon, in response to stress determined by phenolic-derived materials.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/318314
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