Management of Osmotic Stress by
            <i>Bacillus Subtilis</i>
            : Genetics and Physiology

Hoffmann, Tamara; Bremer, Erhard

doi:10.1002/9781119004813.ch63

Cited by 29 publications

(85 citation statements)

References 136 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To functionally study the OpuB and OpuC ABC transporters and their mutant derivatives, we constructed a chassis strain (TMB118) (Supporting Information Table S1) that lacked, with the exception of the l ‐proline osmolyte transporter OpuE (von Blohn et al ., ; Hoffmann et al ., ), all osmostress protectant uptake systems (OpuA, OpuB, OpuC, OpuD) operating in B. subtilis (Hoffmann and Bremer, 2016; 2017) (Fig. ).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

From substrate specificity to promiscuity: hybrid ABC transporters for osmoprotectants

Teichmann

Chen

Hoffmann

et al. 2017

Molecular Microbiology

Self Cite

View full text Add to dashboard Cite

The ABC-transporters OpuB and OpuC from Bacillus subtilis function as osmoprotectant import systems. Their structural genes have most likely evolved through a duplication event but the two transporters are remarkably different in their substrate profile. OpuB possesses narrow substrate specificity, while OpuC is promiscuous. We assessed the functionality of hybrids between these two ABC-transporters by reciprocally exchanging the coding regions for the OpuBC and OpuCC substrate-binding proteins between the corresponding opuB and opuC operons. Substantiating the critical role of the binding protein in setting the substrate specificity of ABC transporters, OpuB::OpuCC turned into a promiscuous system, while OpuC::OpuBC now exhibited narrow substrate specificity. Both hybrid transporters possessed a high affinity for their substrates but the transport capacity of the OpuB::OpuCC system was moderate due to the synthesis of only low amounts of the xenogenetic OpuCC protein. Suppressor mutations causing single amino acid substitutions in the GbsR repressor controlling the choline to glycine betaine biosynthesis pathway greatly improved OpuB::OpuCC-mediated compatible solute import through transcriptional up-regulation of the hybrid opuB::opuCC operon. Collectively, we demonstrate for the first time that one can synthetically switch the substrate specificity of a given ABC transporter by combining its core components with a xenogenetic ligand-binding protein.

show abstract

Section: Resultsmentioning

confidence: 99%

“…Among the five osmoprotectant uptake systems (OpuA–OpuE) operating in B. subtilis (Hoffmann and Bremer, 2016; 2017), the OpuB and OpuC ABC transporters stand out (Fig. ).…”

Section: Introductionmentioning

confidence: 99%

From substrate specificity to promiscuity: hybrid ABC transporters for osmoprotectants

Teichmann

Chen

Hoffmann

et al. 2017

Molecular Microbiology

Self Cite

View full text Add to dashboard Cite

show abstract

“…In a further step of our analysis, we quantitated the amounts of the proline biosynthetic proteins of the M10 derivative (strain MDB28) through targeted proteomics and compared these values with those of its parent strain MDB20. For this set of experiments we exposed the cells to severe osmotic stress (SMM with 1.2 M NaCl) (Boch et al ., ), growth conditions that have been used in the past for most physiological studies addressing the response of B. subtilis to high salinity environments (Hoffmann and Bremer, ). Under these growth conditions, expression of the proHJ ‐reporter fusion was enhanced about 3.9‐fold at high salinity, while the transcriptional activity of its M10 promoter mutant derivative was only stimulated about 1.3‐fold.…”

Section: Resultsmentioning

confidence: 99%

“…In its varied habitats, B. subtilis has to cope with fluctuations in the external osmolarity (Hoffmann et al ., ; Hoffmann and Bremer, ). It adjusts physiologically to increases in the environmental osmolarity through synthesis of the compatible solutes proline and glycine betaine (from the precursor choline), and the import of a large set of osmostress protectants via the osmotically controlled family of Opu transport systems (Hoffmann and Bremer, ). Among the 15 naturally occurring compounds B. subtilis can exploit for osmostress protection (Hoffmann and Bremer, ), proline is the only one it can synthesize de novo (Whatmore et al ., ; Brill et al ., ) and is also the only one which it can catabolize (Belitsky, ; Moses et al ., ).…”

Section: Introductionmentioning

confidence: 99%

“…Whatever signal perception mechanism(s) is used by B. subtilis to detect increases in the external osmolarity (Hoffmann and Bremer, ), the ensuing signal transduction process must eventually converge on the proHJ promoter. Since its salient features are not understood with respect to osmotic control, we have carried out a detailed site‐directed mutagenesis study focusing on key elements of this promoter.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis of the compatible solute proline by Bacillus subtilis: point mutations rendering the osmotically controlled proHJ promoter hyperactive

Hoffmann

Bleisteiner

Sappa

et al. 2017

Environmental Microbiology

Self Cite

View full text Add to dashboard Cite

The ProJ and ProH enzymes of Bacillus subtilis catalyse together with ProA (ProJ-ProA-ProH), osmostress-adaptive synthesis of the compatible solute proline. The proA-encoded gamma-glutamyl phosphate reductase is also used for anabolic proline synthesis (ProB-ProA-ProI). Transcription of the proHJ operon is osmotically inducible whereas that of the proBA operon is not. Targeted and quantitative proteome analysis revealed that the amount of ProA is not limiting for the interconnected anabolic and osmostress-responsive proline production routes. A key player for enhanced osmostress-adaptive proline production is the osmotically regulated proHJ promoter. We used site-directed mutagenesis to study the salient features of this stress-responsive promoter. Two important features were identified: (i) deviations of the proHJ promoter from the consensus sequence of SigA-type promoters serve to keep transcription low under non-inducing growth conditions, while still allowing a finely tuned induction of transcriptional activity when the external osmolarity is increased and (ii) a suboptimal spacer length for SigA-type promoters of either 16-bp (the natural proHJ promoter), or 18-bp (a synthetic promoter variant) is strictly required to allow regulation of promoter activity in proportion to the external salinity. Collectively, our data suggest that changes in the local DNA structure at the proHJ promoter are important determinants for osmostress-inducibility of transcription.

show abstract

The many faces of the unusual biofilm activator RemA

et al. 2022

Self Cite

View full text Add to dashboard Cite

Biofilms can be viewed as tissue‐like structures in which microorganisms are organized in a spatial and functional sophisticated manner. Biofilm formation requires the orchestration of a highly integrated network of regulatory proteins to establish cell differentiation and production of a complex extracellular matrix. Here, we discuss the role of the essential Bacillus subtilis biofilm activator RemA. Despite intense research on biofilms, RemA is a largely underappreciated regulatory protein. RemA forms donut‐shaped octamers with the potential to assemble into dimeric superstructures. The presumed DNA‐binding mode suggests that RemA organizes its target DNA into nucleosome‐like structures, which are the basis for its role as transcriptional activator. We discuss how RemA affects gene expression in the context of biofilm formation, and its regulatory interplay with established components of the biofilm regulatory network, such as SinR, SinI, SlrR, and SlrA. We emphasize the additional role of RemA played in nitrogen metabolism and osmotic‐stress adjustment.

show abstract

Management of Osmotic Stress by Bacillus Subtilis : Genetics and Physiology

Cited by 29 publications

References 136 publications

From substrate specificity to promiscuity: hybrid ABC transporters for osmoprotectants

From substrate specificity to promiscuity: hybrid ABC transporters for osmoprotectants

Synthesis of the compatible solute proline by Bacillus subtilis: point mutations rendering the osmotically controlled proHJ promoter hyperactive

The many faces of the unusual biofilm activator RemA

Contact Info

Product

Resources

About