H-NS involved in positive regulation of glycerol dehydratase gene expression in Klebsiella pneumoniae 2e.

Autor:	Li L; International Cooperation Base of Science and Technology Innovation on Forest Resource Biotechnology, Central South University of Forestry and Technology, Changsha, China.; Hunan Provincial Key Laboratory of Forestry Biotechnology, Central South University of Forestry and Technology, Changsha, China.; Economic Forest Variety Creation Center, Yuelushan National Laboratory of Seed Industry, Changsha, China., Li Q; International Cooperation Base of Science and Technology Innovation on Forest Resource Biotechnology, Central South University of Forestry and Technology, Changsha, China.; Hunan Provincial Key Laboratory of Forestry Biotechnology, Central South University of Forestry and Technology, Changsha, China.; Economic Forest Variety Creation Center, Yuelushan National Laboratory of Seed Industry, Changsha, China., Xiao Y; International Cooperation Base of Science and Technology Innovation on Forest Resource Biotechnology, Central South University of Forestry and Technology, Changsha, China.; Hunan Provincial Key Laboratory of Forestry Biotechnology, Central South University of Forestry and Technology, Changsha, China.; Economic Forest Variety Creation Center, Yuelushan National Laboratory of Seed Industry, Changsha, China., Ma J; International Cooperation Base of Science and Technology Innovation on Forest Resource Biotechnology, Central South University of Forestry and Technology, Changsha, China.; Hunan Provincial Key Laboratory of Forestry Biotechnology, Central South University of Forestry and Technology, Changsha, China.; Economic Forest Variety Creation Center, Yuelushan National Laboratory of Seed Industry, Changsha, China., Liu G-Q; International Cooperation Base of Science and Technology Innovation on Forest Resource Biotechnology, Central South University of Forestry and Technology, Changsha, China.; Hunan Provincial Key Laboratory of Forestry Biotechnology, Central South University of Forestry and Technology, Changsha, China.; Economic Forest Variety Creation Center, Yuelushan National Laboratory of Seed Industry, Changsha, China.
Jazyk:	angličtina
Zdroj:	Applied and environmental microbiology [Appl Environ Microbiol] 2024 Aug 21; Vol. 90 (8), pp. e0007524. Date of Electronic Publication: 2024 Jul 12.
DOI:	10.1128/aem.00075-24
Abstrakt:	Glycerol dehydratase is the key and rate-limiting enzyme in the 1,3-propanediol synthesis pathway of Klebsiella pneumoniae , which determined the producing rate and yield of 1,3-propanediol. However, the expression regulation mechanism of glycerol dehydratase gene dhaB remains poorly unknown. In this study, a histone-like nucleoid-structuring (H-NS) protein was identified and characterized as the positive transcription regulator for dhaB expression in K. pneumoniae 2e, which exhibited high tolerance against crude glycerol in our previous study. Deletion of hns gene significantly decreased the transcription level of dhaB in K. pneumoniae 2e, which led to a remarkable defect on strain growth, glycerol dehydratase activity, and 3-hydroxypropanal production during glycerol fermentation. The transcription level of dhaB was significantly up-regulated in crude glycerol relative to pure glycerol, while the inactivation of H-NS resulted in more negative effect for transcription level of dhaB in the former. Though the H-NS expression level was almost comparable in both substrates, its multimer state was reduced in crude glycerol relative to pure glycerol, suggesting that the oligomerization state of H-NS might have contributed for positive regulation of dhaB expression. Furthermore, electrophoretic mobility shift and DNase I footprinting assays showed that H-NS could directly bind to the upstream promoter region of dhaB by recognizing the AT-rich region. These findings provided new insight into the transcriptional regulation mechanism of H-NS for glycerol dehydratase expression in K. pneumoniae , which might offer new target for engineering bacteria to industrially produce 1,3-propanediol.IMPORTANCEThe biological production of 1,3-propanediol from glycerol by microbial fermentation shows great promising prospect on industrial application. Glycerol dehydratase catalyzes the penultimate step in glycerol metabolism and is regarded as one of the key and rate-limiting enzymes for 1,3-propanediol production. H-NS was reported as a pleiotropic modulator with negative effects on gene expression in most studies. Here, we reported for the first time that the expression of glycerol dehydratase gene is positively regulated by the H-NS. The results provide insight into a novel molecular mechanism of H-NS for positive regulation of glycerol dehydratase gene expression in K. pneumoniae , which holds promising potential for facilitating construction of engineering highly efficient 1,3-propanediol-producing strains. Competing Interests: The authors declare no conflict of interest.
Databáze:	MEDLINE
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