Functional characterization of the transcription regulator WhiB1 from Gordonia sp. IITR100

Abstract

WhiB is a transcription regulator which has been reported to be involved in the regulation of cell morphogenesis, cell division, antibiotic resistance, stress, etc., in several members of the family Actinomycetes . The present study describes functional characterization of a WhiB family protein, WhiB1 (protein ID: WP_065632651.1), from Gordonia sp. IITR100. We demonstrate that WhiB1 affects chromosome segregation and cell morphology in recombinant Escherichia coli , Gordonia sp. IITR100 as well as in Rhodococcus erythropolis . Multiple sequence alignment suggests that WhiB1 is a conserved protein among members of the family Actinomycetes . It has been reported that overexpression of WhiB1 leads to repression of the biodesulfurization operon in recombinant E. coli , Gordonia sp. IITR100 and R. erythropolis . A WhiB1-mut containing a point mutation Q116A in the DNA binding domain of WhiB1 led to partial alleviation of repression of the biodesulfurization operon. We show for the first time that the WhiB family protein WhiB1 is also involved in repression of the biodesulfurization operon by directly binding to the dsz promoter DNA.

The interplay between sulfur assimilation and biodesulfurization phenotype in Rhodococcus qingshengii IGTS8: Insights into a regulatory role of the reverse transsulfuration pathway

“…Importantly, homologues of CysK, CysE, and CymR are harbored within the IGTS8 genome (Blast analysis; Data not shown). Once activated, CymR (74,75) -or some other global regulator -could have a direct repressive effect on the dsz operon or modulate the regulators DszGR and WhiB1 (6)(7)(8). In addition to DszGR, the general DNA binding protein IHF was also shown to be necessary for P dsz promoter activity, but its role has not been validated via knockout of the mihf gene in R. qingshengii IGTS8 or Gordonia sp.…”

“…This hypothesis is in line with the complete lack of biodesulfurization activity and the non-detectable dsz genes expression that was observed for the wt and knockout strains, in the presence of exogenously supplemented cysteine as the sole sulfur source. The mechanistic details of cysteine effects on dsz repression have not been elucidated in R. qingshengii IGTS8, therefore we cannot exclude a direct binding of the metabolite to a homologue of the dsz operon repressor WhiB1 (8). However, it is possible that cysteine promotes the CysK-CymR complex formation, via inhibition of the CysE-CysK bienzyme complex (70, 71).…”

“…Mechanistic insight into the molecular regulation of dsz operon was gained recently with the identification of the TetR family activator DszGR, and the WhiB1 repressor, both derived from the desulfurizing bacterium Gordonia sp. IITR100 (6)(7)(8). Binding of DszGR to the promoter DNA induces an initial bend in Gordonia sp.…”

Interplay between Sulfur Assimilation and Biodesulfurization Activity in Rhodococcus qingshengii IGTS8: Insights into a Regulatory Role of the Reverse Transsulfuration Pathway

“…Mechanistic insight into the molecular regulation of the dsz operon was gained recently with the identification of the TetR family activator DszGR and the WhiB1 repressor, both derived from the desulfurizing bacterium Gordonia sp. strain IITR100 ( 6 – 8 ). Binding of DszGR to the promoter DNA induces an initial bend in the Gordonia sp.…”

Characterization of a dszEABC operon providing fast growth on dibenzothiophene and construction of broad‐host‐range biodesulfurization catalysts

“…To date, only the Gordonia sp. IITR100 system has been characterized and shown to involve a TetR‐family activator (Murarka et al ., 2019; Murarka and Srivastava, 2019) and a global repressor, WhiB1 (Murarka et al ., 2020). Both repressor and activator have been shown to bind at the dsz promoter region.…”