scholarly journals The transcriptional regulator LevR of Bacillus subtilis has domains homologous to both sigma 54- and phosphotransferase system-dependent regulators.

1991 ◽  
Vol 88 (6) ◽  
pp. 2212-2216 ◽  
Author(s):  
M. Debarbouille ◽  
I. Martin-Verstraete ◽  
A. Klier ◽  
G. Rapoport
Keyword(s):  
Bacillus Subtilis ◽  
Transcriptional Regulator ◽  
Phosphotransferase System ◽  
Sigma 54

scholarly journals Conformational transitions induced by γ-amino butyrate binding in GabR, a bacterial transcriptional regulator

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mario Frezzini ◽  
Leonardo Guidoni ◽  
Stefano Pascarella
Keyword(s):  
Molecular Dynamics ◽  
Bacillus Subtilis ◽  
Closed Form ◽  
Molecular Mechanism ◽  
Aspartate Aminotransferase ◽  
Transcriptional Regulator ◽  
Transcription Activation ◽  
Conformational Transitions ◽  
Winged Helix ◽  
Gaba Binding

AbstractGabR from Bacillus subtilis is a transcriptional regulator of the MocR subfamily of GntR regulators. The MocR architecture is characterized by the presence of an N-terminal winged-Helix-Turn-Helix domain and a C-terminal domain folded as the pyridoxal 5′-phosphate (PLP) dependent aspartate aminotransferase (AAT). The two domains are linked by a peptide bridge. GabR activates transcription of genes involved in γ-amino butyrate (GABA) degradation upon binding of PLP and GABA. This work is aimed at contributing to the understanding of the molecular mechanism underlying the GabR transcription activation upon GABA binding. To this purpose, the structure of the entire GabR dimer with GABA external aldimine (holo-GABA) has been reconstructed using available crystallographic data. The structure of the apo (without any ligand) and holo (with PLP) GabR forms have been derived from the holo-GABA. An extensive 1 μs comparative molecular dynamics (MD) has been applied to the three forms. Results showed that the presence of GABA external aldimine stiffens the GabR, stabilizes the AAT domain in the closed form and couples the AAT and HTH domains dynamics. Apo and holo GabR appear more flexible especially at the level of the HTH and linker portions and small AAT subdomain.

Crystal structure of YfiR, an unusual TetR/CamR-type putative transcriptional regulator from Bacillus subtilis

2006 ◽  
Vol 65 (1) ◽  
pp. 255-257 ◽  
Author(s):  
Shyamala S. Rajan ◽  
Xiaojing Yang ◽  
Ludmilla Shuvalova ◽  
Frank Collart ◽  
Wayne F. Anderson
Keyword(s):  
Crystal Structure ◽  
Bacillus Subtilis ◽  
Transcriptional Regulator

PTS-Mediated Regulation of the Transcription Activator MtlR from Different Species: Surprising Differences despite Strong Sequence Conservation

2015 ◽  
Vol 25 (2-3) ◽  
pp. 94-105 ◽  
Author(s):  
Philippe Joyet ◽  
Meriem Derkaoui ◽  
Houda Bouraoui ◽  
Josef Deutscher
Keyword(s):  
Bacillus Subtilis ◽  
Lactobacillus Casei ◽  
Sequence Conservation ◽  
Geobacillus Stearothermophilus ◽  
Transcription Activator ◽  
Phosphotransferase System ◽  
Transcription Regulator ◽  
Regulatory Domains ◽  
Genes Encoding ◽  
Enzyme I

The hexitol <smlcap>D</smlcap>-mannitol is transported by many bacteria via a phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS). In most Firmicutes, the transcription activator MtlR controls the expression of the genes encoding the <smlcap>D</smlcap>-mannitol-specific PTS components and <smlcap>D</smlcap>-mannitol-1-P dehydrogenase. MtlR contains an N-terminal helix-turn-helix motif followed by an Mga-like domain, two PTS regulation domains (PRDs), an EIIB<sup>Gat</sup>- and an EIIA<sup>Mtl</sup>-like domain. The four regulatory domains are the target of phosphorylation by PTS components. Despite strong sequence conservation, the mechanisms controlling the activity of MtlR from <i>Lactobacillus casei</i>, <i>Bacillus subtilis</i> and <i>Geobacillus stearothermophilus</i> are quite different. Owing to the presence of a tyrosine in place of the second conserved histidine (His) in PRD2, <i>L. casei</i> MtlR is not phosphorylated by Enzyme I (EI) and HPr. When the corresponding His in PRD2 of MtlR from <i>B. subtilis</i> and <i>G. stearothermophilus</i> was replaced with alanine, the transcription regulator was no longer phosphorylated and remained inactive. Surprisingly, <i>L. casei</i> MtlR functions without phosphorylation in PRD2 because in a <i>ptsI</i> (EI) mutant MtlR is constitutively active. EI inactivation prevents not only phosphorylation of HPr, but also of the PTS<sup>Mtl</sup> components, which inactivate MtlR by phosphorylating its EIIB<sup>Gat</sup>- or EIIA<sup>Mtl</sup>-like domain. This explains the constitutive phenotype of the <i>ptsI</i> mutant. The absence of EIIB<sup>Mtl</sup>-mediated phosphorylation leads to induction of the <i>L. casei</i><i>mtl </i>operon. This mechanism resembles <i>mtlARFD</i> induction in <i>G. stearothermophilus</i>, but differs from EIIA<sup>Mtl</sup>-mediated induction in <i>B. subtilis</i>. In contrast to <i>B. subtilis</i> MtlR, <i>L. casei</i> MtlR activation does not require sequestration to the membrane via the unphosphorylated EIIB<sup>Mtl</sup> domain.

scholarly journals Regulation of Lactobacillus casei Sorbitol Utilization Genes Requires DNA-Binding Transcriptional Activator GutR and the Conserved Protein GutM

2008 ◽  
Vol 74 (18) ◽  
pp. 5731-5740 ◽  
Author(s):  
Cristina Alcántara ◽  
Luz Adriana Sarmiento-Rubiano ◽  
Vicente Monedero ◽  
Josef Deutscher ◽  
Gaspar Pérez-Martínez ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Sequence Comparison ◽  
Promoter Region ◽  
Lactobacillus Casei ◽  
Transcriptional Regulator ◽  
Transcriptional Activator ◽  
Regulation Mechanism ◽  
Phosphotransferase System ◽  
Footprint Analysis ◽  
Operon Expression

ABSTRACT Sequence analysis of the five genes (gutRMCBA) downstream from the previously described sorbitol-6-phosphate dehydrogenase-encoding Lactobacillus casei gutF gene revealed that they constitute a sorbitol (glucitol) utilization operon. The gutRM genes encode putative regulators, while the gutCBA genes encode the EIIC, EIIBC, and EIIA proteins of a phosphoenolpyruvate-dependent sorbitol phosphotransferase system (PTSGut). The gut operon is transcribed as a polycistronic gutFRMCBA messenger, the expression of which is induced by sorbitol and repressed by glucose. gutR encodes a transcriptional regulator with two PTS-regulated domains, a galactitol-specific EIIB-like domain (EIIBGat domain) and a mannitol/fructose-specific EIIA-like domain (EIIAMtl domain). Its inactivation abolished gut operon transcription and sorbitol uptake, indicating that it acts as a transcriptional activator. In contrast, cells carrying a gutB mutation expressed the gut operon constitutively, but they failed to transport sorbitol, indicating that EIIBCGut negatively regulates GutR. A footprint analysis showed that GutR binds to a 35-bp sequence upstream from the gut promoter. A sequence comparison with the presumed promoter region of gut operons from various firmicutes revealed a GutR consensus motif that includes an inverted repeat. The regulation mechanism of the L. casei gut operon is therefore likely to be operative in other firmicutes. Finally, gutM codes for a conserved protein of unknown function present in all sequenced gut operons. A gutM mutant, the first constructed in a firmicute, showed drastically reduced gut operon expression and sorbitol uptake, indicating a regulatory role also for GutM.

Regulation of the Bacillus subtilis mannitol utilization genes: promoter structure and transcriptional activation by the wild-type regulator (MtlR) and its mutants

Microbiology ◽  
2014 ◽  
Vol 160 (1) ◽  
pp. 91-101 ◽  
Author(s):  
Kambiz Morabbi Heravi ◽  
Josef Altenbuchner
Keyword(s):  
Bacillus Subtilis ◽  
Transcriptional Activation ◽  
Transcription Initiation ◽  
Phosphotransferase System ◽  
Mobility Shift ◽  
Dnase I Footprinting ◽  
Proposed Model ◽  
Rna Polymerase Holoenzyme ◽  
Electrophoretic Mobility Shift Assays

Expression of mannitol utilization genes in Bacillus subtilis is directed by P mtlA , the promoter of the mtlAFD operon, and P mtlR , the promoter of the MtlR activator. MtlR contains phosphoenolpyruvate-dependent phosphotransferase system (PTS) regulation domains, called PRDs. The activity of PRD-containing MtlR is mainly regulated by the phosphorylation/dephosphorylation of its PRDII and EIIBGat-like domains. Replacing histidine 342 and cysteine 419 residues, which are the targets of phosphorylation in these two domains, by aspartate and alanine provided MtlR-H342D C419A, which permanently activates P mtlA in vivo. In the mtlR-H342D C419A mutant, P mtlA was active, even when the mtlAFD operon was deleted from the genome. The mtlR-H342D C419A allele was expressed in an Escherichia coli strain lacking enzyme I of the PTS. Electrophoretic mobility shift assays using purified MtlR-H342D C419A showed an interaction between the MtlR double-mutant and the Cy5-labelled P mtlA and P mtlR DNA fragments. These investigations indicate that the activated MtlR functions regardless of the presence of the mannitol-specific transporter (MtlA). This is in contrast to the proposed model in which the sequestration of MtlR by the MtlA transporter is necessary for the activity of MtlR. Additionally, DNase I footprinting, construction of P mtlA -P licB hybrid promoters, as well as increasing the distance between the MtlR operator and the −35 box of P mtlA revealed that the activated MtlR molecules and RNA polymerase holoenzyme likely form a class II type activation complex at P mtlA and P mtlR during transcription initiation.

scholarly journals Characterization of Glucose-Specific Catabolite Repression-Resistant Mutants of Bacillus subtilis: Identification of a Novel Hexose:H+ Symporter

1998 ◽  
Vol 180 (3) ◽  
pp. 498-504 ◽  
Author(s):  
Ian T. Paulsen ◽  
Sylvie Chauvaux ◽  
Peter Choi ◽  
Milton H. Saier
Keyword(s):  
Bacillus Subtilis ◽  
Catabolite Repression ◽  
Genetic Background ◽  
Insertional Mutagenesis ◽  
Sequence Similarity ◽  
Major Facilitator Superfamily ◽  
Phosphotransferase System ◽  
E Coli ◽  
Major Facilitator

ABSTRACT Insertional mutagenesis was conducted on Bacillus subtilis cells to screen for mutants resistant to catabolite repression. Three classes of mutants that were resistant to glucose-promoted but not mannitol-promoted catabolite repression were identified. Cloning and sequencing of the mutated genes revealed that the mutations occurred in the structural genes for (i) enzyme II of the phosphoenolpyruvate-glucose phosphotransferase (PtsG), (ii) antiterminator GlcT, which controls PtsG synthesis, and (iii) a previously uncharacterized carrier of the major facilitator superfamily, which we have designated GlcP. The last protein exhibits greatest sequence similarity to the fucose:H+ symporter ofEscherichia coli and the glucose/galactose:H+symporter of Brucella abortus. In a wild-type B. subtilis genetic background, theglcP::Tn10 mutation (i) partially but specifically relieved glucose- and sucrose-promoted catabolite repression, (ii) reduced the growth rate in minimal glucose medium, and (iii) reduced rates of [14C]glucose and [14C]methyl α-glucoside uptake. In a Δptsgenetic background no phenotype was observed, suggesting that expression of the glcP gene required a functional phosphotransferase system. When overproduced in a Δptsmutant of E. coli, GlcP could be shown to specifically transport glucose, mannose, 2-deoxyglucose and methyl α-glucoside with low micromolar affinities. Accumulation of the nonmetabolizable glucose analogs was demonstrated, and inhibitor studies suggested a dependency on the proton motive force. We conclude that B. subtilis possesses at least two distinct routes of glucose entry, both of which contribute to the phenomenon of catabolite repression.

Sign in / Sign up

Export Citation Format

Share Document