Tian_2019_Toxins.(Basel)_11

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Title : CesH Represses Cereulide Synthesis as an Alpha\/Beta Fold Hydrolase in Bacillus cereus - Tian_2019_Toxins.(Basel)_11_

Author(s) : Tian S , Xiong H , Geng P , Yuan Z , Hu X

Ref : Toxins (Basel) , 11 : , 2019

Abstract : Cereulide is notorious as a heat-stable emetic toxin produced by Bacillus cereus and glucose is supposed to be an ingredient supporting its formation. This study showed that glucose addition benefited on cell growth and the early transcription of genes involved in substrate accumulation and toxin synthesis, but it played a negative role in the final production of cereulide. Meanwhile, a lasting enhancement of cesH transcription was observed with the addition of glucose. Moreover, the cereulide production in DeltacesH was obviously higher than that in the wild type. This indicates that CesH has a repression effect on cereulide production. Bioinformatics analysis revealed that CesH was an alpha/beta hydrolase that probably associated with the cell membrane, which was verified by subcellular localization. The esterase activity against para-nitrophenyl acetate (PNPC2) of the recombinant CesH was confirmed. Although no sign of ester bond cleavage in cereulide or valinomycin was demonstrated in in vitro assays, CesH could reverse the cereulide analogue sensitivity of Bacillus subtilis in vivo, by which toxin degradation was facilitated. Moreover, site directed mutations identified that the conserved catalytic triad of CesH might consist of Serine 86, Glutamate 199, and Histidine 227. These results help us to understand the regulation of cereulide production and provide clues for developing control measurements.

ESTHER : Tian_2019_Toxins.(Basel)_11_

PubMedSearch : Tian_2019_Toxins.(Basel)_11_

PubMedID: 31010094

Gene_locus related to this paper: bacce-q20cj2

Tian_2019_Toxins.(Basel)_11_

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