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At least 19 recordsLinked to original sources

PubMed2024

Immunopeptidomics Mapping of Listeria monocytogenes T Cell Epitopes in Mice.

Listeria monocytogenes is a foodborne intracellular bacterial model pathogen. Protective immunity against Listeria depends on an effective CD8+ T cell response, but very few T cell epitopes are known in mice as a common animal infection model for listeriosis. To identify epitopes, we screened for Listeria immunopeptides presented in the spleen of infected mice by mass spectrometry-based immunopeptidomics. We mapped more than 6000 mouse self-peptides presented on MHC class I molecules, including 12 high confident Listeria peptides from 12 different bacterial proteins. Bacterial immunopeptides with confirmed fragmentation spectra were further tested for their potential to activate CD8+ T cells, revealing VTYNYINI from the putative cell wall surface anchor family protein LMON_0576 as a novel bona fide peptide epitope. The epitope showed high biological potency in a prime boost model and can be used as a research tool to probe CD8+ T cell responses in the mouse models of Listeria infection. Together, our results demonstrate the power of immunopeptidomics for bacterial antigen identification.

Animals↗

PubMed2026

Prediction of bacterial protein-compound interactions with only positive samples.

MOTIVATION: Prediction of Compound-Protein Interactions (CPI) in bacteria is crucial to advance various pharmaceutical and chemical engineering fields, including biocatalysis, drug discovery, and industrial processing. However, current CPI models cannot be applied for bacterial CPI prediction due to the lack of curated negative interaction samples. RESULTS: We propose a novel Positive-Unlabeled (PU) learning framework, named BIN-PU, to address this limitation. BIN-PU generates pseudo positive and negative labels from known positive interaction data, enabling effective training of deep learning models for CPI prediction. We also propose a weighted positive loss function that weights to truly positive samples. We have validated BIN-PU coupled with multiple CPI backbone models, comparing the performance with the existing PU models using bacterial cytochrome P450 (CYP) data. Extensive experiments demonstrate the superiority of BIN-PU over the benchmark models in predicting CPIs with only truly positive samples. Furthermore, we have validated BIN-PU on additional bacterial proteins obtained from literature review, human CYP datasets, and uncurated data for its reproducibility. We have also validated the CPI prediction for the uncurated CYP data with biological and biophysical experiments. BIN-PU represents a significant advancement in CPI prediction for bacterial proteins, opening new possibilities for improving predictive models in related biological interaction tasks. AVAILABILITY AND IMPLEMENTATION: The source code and data are available at https://github.com/datax-lab/CYP.

Bacterial Proteins↗

PubMed2025

The small bacterial membrane protein YohP induces nucleoid condensation in E. coli and inhibits oligomerization of antimicrobial peptides.

Prokaryotic organisms execute multiple stress response mechanisms in order to cope with rapidly changing environments. Some mechanisms respond to specific cues, such as the OxyR-dependent response to hydrogen peroxide or the SOS-response that is induced upon DNA-damage. These specific responses complement general mechanisms that respond to multiple and diverse stressors. One example is nucleoid condensation, which is a rapid and effective mechanism for genome protection and observed in response to various stresses, including entry into stationary phase. Recently, the upregulation of small membrane proteins (SMPs) in response to stress was observed, but details on how this emerging class of proteins modulate the stress response is largely unknown. Here, we demonstrate that the production of two SMPs, YohP and YncL, cause nucleoid condensation in Escherichia coli. Nucleoid condensation is the result of YohP-/YncL-induced sublethal membrane depolarization, which induces the phage-shock response and leads to a reduction of global protein synthesis. YohP production also prevents the oligomerization of the antimicrobial peptide magainin-2 in the E. coli membrane and reduces the metabolic activity of E. coli cells. Thus, the synthesis of YohP and likely of other SMPs potentially protects bacterial cells against some unfavorable conditions by shifting them into a metabolically silent state.

YncL↗

PubMed2025

Use of shotgun immunoproteomics for the development of protein vaccines against Edwardsiella piscicida.

Edwardsiella piscicida is an important emerging pathogen in various cultured fish species. This study aimed to identify immunogenic E. piscicida proteins and evaluate these antigens as protein vaccines for use in aquaculture. Shotgun immunoproteomics using anti-E. piscicida serum from rainbow trout (Oncorhynchus mykiss) and channel catfish (Ictalurus punctatus) (♀) × blue catfish (Ictalurus furcatus) (♂) hybrids inoculated with formalin-killed whole-bacteria preparations identified 36 candidate immunogenic E. piscicida proteins. The chaparonin GroEL, the glycine 2TM zipper domain-containing protein (GlyZip), and coproporphyrinogen-III oxidase (COPIII) were used to orally (PO) and intra-coelomically (IC) immunize Chinook salmon (Oncorhynchus tshawytscha). Fish IC vaccinated with either GlyZip or COPIII demonstrated a slight, but non-significant, improvement in survival post-challenge with E. piscicida S11-285. Surprisingly, fish IC or PO vaccinated with GroEL displayed an anti-protective effect (RPS = -184 % and RPS = -76 %, respectively) against subsequent challenge. All IC vaccinated fish generated a strong specific antibody response against the immunizing protein, and sham vaccinated fish challenged with E. piscicida S11-285 generated a significantly higher specific antibody response to the GroEL and GlyZip proteins than negative control fish, suggesting that shotgun immunoproteomics was effective for detection of immunogenic bacterial proteins that can stimulate humoral immune responses in the host fish.

Animals↗

PubMed2025

Large Quantities of Bacterial DNA and Protein in Common Dietary Protein Source Used in Microbiome Studies.

Diet has been shown to greatly impact the intestinal microbiota. To understand the role of individual dietary components, defined diets with purified components are frequently used in diet-microbiota studies. Defined diets frequently use purified casein as the protein source. Previous work indicated that casein contains microbial DNA potentially impacting results of microbiome studies. Other diet-based microbially derived molecules that may impact microbiome measurements, such as proteins detected by metaproteomics, have not been determined for casein. Additionally, other protein sources used in microbiome studies have not been characterized for their microbial content. We used metagenomics and metaproteomics to identify and quantify microbial DNA and protein in a casein-based defined diet to better understand potential impacts on metagenomic and metaproteomic microbiome studies. We further tested six additional defined diets with purified protein sources with an integrated metagenomic-metaproteomic approach and found that contaminating microbial protein is unique to casein within the tested set as microbial protein was not identified in diets with other protein sources. We also illustrate the contribution of diet-derived microbial protein in diet-microbiota studies by metaproteomic analysis of stool samples from germ-free mice (GF) and mice with a conventional microbiota (CV) following consumption of diets with casein and non-casein protein. This study highlights a potentially confounding factor in diet-microbiota studies that must be considered through evaluation of the diet itself within a given study.

Animals↗

PubMed2025

Identification of gene targets regulated by the IclR-like regulator SL1344_3500 in Salmonella Typhimurium.

Transcriptional regulation of metabolic operons is important for optimal carbohydrate use and for mitigating the accumulation of toxic intermediates. Here, we characterize SL1344_3500, encoding a putative IclR-like regulator in Salmonella enterica Typhimurium. We present genetic and transcriptional evidence that it regulates the expression of two neighboring operons, one designated here as xynABC, enables utilization of xylonate as a sole carbon source. Furthermore, our findings indicate that SL1344_3500 is important for luminal growth in several mouse models, exerting its effects through the suppression of the xynABC operon. Based on the observation that the ΔSL1344_3500 deletion can be stably complemented in vivo, we developed a plasmid stabilization strategy. This gene complementation approach shows promise for generating stable gene reporters for long-term colonization experiments.IMPORTANCEUnderstanding transcriptional regulation in Salmonella enterica Typhimurium is crucial for revealing how enteric pathogens optimize metabolism to compete with commensals in the gut. SL1344_3500, an IclR-like transcriptional regulator controlling genes linked to sugar acid metabolism, is essential for luminal growth in mouse models through gene suppression and represents a potential target for antimicrobial development. Based on these observations, we developed stable reporter plasmids that use gene complementation of SL1344_3500 to prevent plasmid loss during long-term in vivo studies.

Salmonella typhimurium↗

PubMed2024

Revealing novel protein interaction partners of glyphosate in Escherichia coli.

Despite all debates about its safe use, glyphosate remains the most widely applied active ingredient in herbicide products, with renewed approval in the European Union until 2033. Non-target organisms are commonly exposed to glyphosate as a matter of its mode of application, with its broader environmental and biological impacts remaining under investigation. Glyphosate displays structural similarity to phosphoenolpyruvate (PEP), thereby competitively inhibiting the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), crucial for the synthesis of aromatic amino acids in plants, fungi, bacteria, and archaea. Most microbes, including the gut bacterium Escherichia coli (E. coli), possess a glyphosate-sensitive class I EPSPS, making them vulnerable to glyphosate's effects. Yet, little is known about glyphosate's interactions with other bacterial proteins or its broader modes of action at the proteome level. Here, we employed a quantitative proteomics and thermal proteome profiling (TPP) approach to identify novel protein binding partners of glyphosate in the E. coli proteome. Glyphosate exposure significantly altered amino acid synthesizing pathways. The abundance of shikimate pathway proteins was increased, suggesting a compensatory mechanism. Extracellular riboflavin concentrations were elevated upon glyphosate exposure, while intracellular levels remained stable. Beyond the target enzyme EPSPS, thermal proteome profiling indicated an effect of glyphosate on the thermal stability of certain proteins, including AroH and ProA, indicating interactions. Similar to the competitive binding between PEP and glyphosate at EPSPS, one reason for the interaction of AroH and ProA with the herbicide could be a high structural similarity between their substrates and glyphosate. Overall, glyphosate induced metabolic disturbances in E. coli, extending beyond its primary target, thereby providing new insights into glyphosate's broader impact on microbial systems.

Glyphosate↗

PubMed2026

Biofilm formation during pneumococcal carriage imprints naturally acquired humoral immunity.

Streptococcus pneumoniae (Spn) colonization of the nasopharynx is a prerequisite for transmission and invasive disease. To investigate how repeated asymptomatic colonization shapes immunity and influences bacterial traits, we developed the Repeated Asymptomatic Murine Pneumococcal Colonization (RAMPC3) model using strains belonging to serotypes: 2 (D39), 3 (WU2), and 4 (TIGR4). Sequential colonization revealed strain- and exposure-order-dependent effects on bacterial burden, with initial colonization yielding robust carriage and subsequent exposures resulting in diminished burden and rapid clearance. Humoral profiling demonstrated antigenic imprinting: the first colonizing strain largely determined IgG and IgA specificity against bacterial proteins, with minimal diversification or expansion after repeated exposures. Reactivity was strongest for biofilm-associated antigens correlating with each strain's biofilm-forming capacity. Notably, experiments using human sera from naturally colonized adults mirrored these findings, with reactivity favoring biofilm antigens independent from capsule. Partial protection as result of colonization was demonstrated as triple-colonized mice had reduced mortality following pneumococcal pneumonia challenge. Likewise, mice colonized with biofilm deficient versions of TIGR4 and then challenged intratracheally with a serotype 6A (6A-10) strain were more likely to develop bacteremia, underscoring the contribution of the biofilm-associated host response to immunity. Finally, IgA responses in nasal-associated lymphoid tissue paralleled serum IgA patterns, validating systemic measurements as a proxy for mucosal immunity. These results reveal that biofilm formation during colonization is a key determinant of humoral immunity and contributes to systemic protection, providing insight into pneumococcal biology and informing strategies to design next-generation interventions.

Animals↗

PubMed2025

Gene Editing and Protein Tagging in the Oomycete Phytophthora infestans Using CRISPR-Cas12a.

Molecular genetic tools such as CRISPR-Cas gene editing systems are invaluable for understanding gene and protein function and revealing the details of a pathogen's life and disease cycles. Here we present protocols for genome editing in Phytophthora infestans, an oomycete with global importance as a pathogen of potato and tomato. Using a vector system that expresses variants of Cas12a from Lachnospiraceae bacterium and its guide RNA from a unified transcript, we first present a method for editing genes through the non-homologous end-joining (NHEJ) pathway. We then describe an application of homology-directed repair (HDR), in which Cas12a is used to fuse a protein-coding gene with a fluorescent or epitope tag. Both methods should be adaptable to many oomycetes other than P. infestans.

Gene Editing↗

PubMed2025

Methods for Cas13a expression and purification for use in CRISPR diagnostics.

The threat of emerging infectious diseases (e.g., SARS-CoV-2 the RNA virus responsible for the COVID-19 pandemic) has highlighted the importance of accurate and rapid testing for screening, patient diagnosis, and effective treatment of infectious disease. Nucleic acid diagnostic tools such as qPCR are considered the gold standard, providing a sensitive, accurate, and robust method of detection. However, these conventional diagnostic platforms are resource intensive, limited in some applications, and are almost always confined to laboratory settings. With the increasing demand for low-cost, rapid, and accurate point-of-care diagnostics, CRISPR-based systems have emerged as powerful tools to augment detection capabilities. Of note is the potent RNA detection enzyme, Leptotrichia buccalis (Lbu) Cas13a, which is capable of rapid RNA detection in complex mixtures with or without pre-amplification. To support its wide-spread use, we describe a detailed method for the expression, purification, and validation of LbuCas13a for use in molecular diagnostics.

SARS-CoV-2↗

PubMed2024

Vaginal Lactobacillus fatty acid response mechanisms reveal a metabolite-targeted strategy for bacterial vaginosis treatment.

Bacterial vaginosis (BV), a common syndrome characterized by Lactobacillus-deficient vaginal microbiota, is associated with adverse health outcomes. BV often recurs after standard antibiotic therapy in part because antibiotics promote microbiota dominance by Lactobacillus iners instead of Lactobacillus crispatus, which has more beneficial health associations. Strategies to promote L. crispatus and inhibit L. iners are thus needed. We show that oleic acid (OA) and similar long-chain fatty acids simultaneously inhibit L. iners and enhance L. crispatus growth. These phenotypes require OA-inducible genes conserved in L. crispatus and related lactobacilli, including an oleate hydratase (ohyA) and putative fatty acid efflux pump (farE). FarE mediates OA resistance, while OhyA is robustly active in the vaginal microbiota and enhances bacterial fitness by biochemically sequestering OA in a derivative form only ohyA-harboring organisms can exploit. OA promotes L. crispatus dominance more effectively than antibiotics in an in vitro BV model, suggesting a metabolite-based treatment approach.

Vaginosis, Bacterial↗

PubMed2026

Genomic analysis of an Arctic marine Tenacibaculum sp. SM2510 reveals its genetic potential for glutathione utilization.

Glutathione is a key intracellular antioxidant, playing a crucial role in resisting oxidative stress and maintaining cellular redox homeostasis. However, the glutathione metabolic capacity of Tenacibaculum remains poorly characterized. In this study, a Gram-stain-negative bacterium, Tenacibaculum sp. SM2510, was isolated from seawater collected from Kongsfjorden, Svalbard, Norway. Genome sequencing revealed that the strain possesses a single circular chromosome of 2,904,982 bp with a G + C content of 31.44%, encoding 2564 protein-coding genes. Genomic analysis indicates that Tenacibaculum sp. SM2510 may directly take up extracellular oxidized glutathione (GSSG) and reduce it to reduced glutathione (GSH) through a reductive pathway, which potentially allows the strain to alleviate the accumulation of reactive oxygen species (ROS) caused by strong ultraviolet radiation and low temperature in polar environments. Furthermore, genomic analysis predicts that the strain degrades GSH to produce essential life-sustaining substances. In conclusion, these results suggest that Tenacibaculum sp. SM2510 may potentially utilize exogenous glutathione for both antioxidant defense and nutrient acquisition through direct GSH degradation, providing new insights into the environmental adaptive evolution of polar marine bacteria.

Tenacibaculum↗

PubMed2026

Polyphosphate acts as an architectural regulator of carbon fixation and nucleoid structure in cyanobacteria.

Polyphosphate (polyP) is a conserved inorganic polymer traditionally viewed as a stress-induced phosphate and energy reserve. In cyanobacteria, however, polyP granules are constitutively present and are frequently observed in close proximity to carboxysomes, the bacterial microcompartments that mediate CO2 fixation. Here, we show that polyP functions as a spatially organized regulator of the photosynthetic cytoplasm in Synechococcus elongatus. PolyP granules localize to the nucleoid and are periodically arranged along the cell axis, independent of the McdAB carboxysome positioning system. Despite this independence, polyP and carboxysomes associate non-randomly, and this association is enhanced when active carboxysome positioning by the McdAB system is disrupted. Loss of polyP synthesis leads to nucleoid expansion, an increased number of smaller carboxysomes with high mobility, and severe defects in growth under ambient CO2. Perturbation of polyP turnover further reveals structural connections to both carboxysomes and thylakoid membranes. Together, these findings identify polyP as an architectural integrator that couples chromosome organization, metabolic compartmentalization, and photosynthetic fitness.IMPORTANCEPolyphosphate (polyP) is a ubiquitous storage polymer found across all three domains of life. In bacteria, polyP is involved in virulence, energy metabolism, DNA structure, and stress. Here, we investigate the physical and functional relationships between polyP and the carboxysome-a carbon-fixing organelle that encapsulates the most abundant enzyme on Earth and is responsible for a significant amount of atmospheric CO2 sequestration. We discover that polyP is important for proper carboxysome assembly and organization in the cell and is also required for robust cell growth under ambient CO2 conditions. As carboxysomes are one class of the broader group of bacterial microcompartments, these findings have broader implications for polyP in the function and organization of the bacterial cytoplasm.

Polyphosphates↗

PubMed2017

The Influence of the Toxin/Antitoxin mazEF on Growth and Survival of Listeria monocytogenes under Stress.

A major factor in the resilience of Listeria monocytogenes is the alternative sigma factor B (σB). Type II Toxin/Antitoxin (TA) systems are also known to have a role in the bacterial stress response upon activation via the ClpP or Lon proteases. Directly upstream of the σB operon in L. monocytogenes is the TA system mazEF, which can cleave mRNA at UACMU sites. In this study, we showed that the mazEF TA locus does not affect the level of persister formation during treatment with antibiotics in lethal doses, but exerts different effects according to the sub-inhibitory stress added. Growth of a ΔmazEF mutant was enhanced relative to the wildtype in the presence of sub-inhibitory norfloxacin and at 42 °C, but was decreased when challenged with ampicillin and gentamicin. In contrast to studies in Staphylococcus aureus, we found that the mazEF locus did not affect transcription of genes within the σB operon, but MazEF effected the expression of the σB-dependent genes opuCA and lmo0880, with a 0.22 and 0.05 fold change, respectively, compared to the wildtype under sub-inhibitory norfloxacin conditions. How exactly this system operates remains an open question, however, our data indicates it is not analogous to the system of S. aureus, suggesting a novel mode of action for MazEF in L. monocytogenes.

Anti-Bacterial Agents↗

PubMed2025

BAV-LLPS: a database of bacterial, archaea, and virus liquid-liquid phase separation proteins.

MOTIVATION: Liquid-liquid phase separation (LLPS) is a key process underlying the formation of biomolecular condensates, such as membrane-less organelles, that compartmentalize biochemical processes inside the cells. While LLPS has been extensively studied in eukaryotes, its role in bacteria, archaea, and viruses remains far less characterized. Recent studies in bacteria have revealed that LLPS-driven condensates play critical roles in RNA processing, stress response, and pathogenicity. Similarly, many viruses exploit LLPS to facilitate crucial steps in their infection cycles, including viral entry, genome replication, assembly, and host immune evasion. RESULTS: In this work, we introduce a hand-curated database of LLPS proteins from bacteria, archaea, and viruses (BAV-LLPS Database). This resource, extended through sequence similarity searches, comprises over 5000 proteins and integrates diverse data including biological annotations, sequence features, predicted disordered regions, LLPS per site probability, and AlphaFold2-based structural models. Additionally, our web server enables users to explore both the curated and homologous derived datasets, providing a platform to uncover evolutionary relationships and intrinsic and differential properties of LLPS proteins across various taxonomic groups. This work seeks to deepen our understanding of LLPS mechanisms beyond eukaryotic organisms, emphasizing their significance across diverse life forms. It also aims to foster the development of specialized predictive tools that will facilitate the exploration and characterization of LLPS processes in a wide array of living organisms, thereby contributing to advancements in both fundamental biological research and applied biomedical sciences. AVAILABILITY AND IMPLEMENTATION: BAV-LLPS DB is freely accessible at https://bav-llps-db.bioinformatica.org/. The data can be retrieved from the website. The source code of the database can be downloaded from https://bav-llps-db.bioinformatica.org/download.

Databases, Protein↗

PubMed2026

Genomic and structural insights into the atpB L173I substitution: modulation of the F₀ rotor architecture in Mycobacterium tuberculosis ATP synthase and altered Bedaquiline binding dynamics.

The F₀F₁ ATP synthase of Mycobacterium tuberculosis (M. tuberculosis) is an essential membrane-embedded rotary motor responsible for ATP synthesis and maintenance of the proton motive force in bacteria. The transmembrane F₀ domain comprises the c-subunit (atpE) and the a-subunit (atpB). Their coordinated interactions are needed for proton translocation and torque generation. Bedaquiline (BDQ), FDA-approved diarylquinoline for the treatment of multidrug-resistant tuberculosis (MDR-TB), targets the F₀ motor by binding at the a-c interface and inhibiting rotary catalysis. To the best of our knowledge, this study represents the first attempt to analyze the effects of mutations in the atpB protein on its structural stability in the F₀ domain, thereby highlighting the novelty of this work. In this study, we integrated Indian whole-genome sequencing (WGS) datasets (PRJNA37907) with long-timescale (1000 ns) membrane-embedded molecular dynamics (MD) simulations. Among 57 atpB mutations identified from WGS analysis, L173I was selected for structural and MD analysis. L173I is located at the atpB-atpE interface near the BDQ-binding region, despite V177L and S184A showing higher prevalence. Comparative MD simulations encompassed four systems: wild-type apo, wild-type with BDQ, L173I apo, and L173I with BDQ. Structural interrogation revealed that the L173I substitution induces subtle destabilization of the global fold of the atpB-atpE complex relative to the apo state, while more critically attenuating inter-subunit contacts between the a-subunit and the c-ring. These perturbations provide a mechanistic rationale for reduced BDQ susceptibility, arising from altered interfacial dynamics rather than complete abrogation of drug binding. This integrative genomic-structural framework advances our understanding of ATP synthase-mediated resistance in M. tuberculosis.

Diarylquinolines↗

PubMed2026

Bacterial stress responses lower mRNA-protein level correlations.

Diverse bacterial pathogens have evolved complex regulatory mechanisms to adapt to various environmental stresses during infection. The uncertainty in mRNA-protein levels in response to environmental stressors complicates our understanding of bacterial physiology and their adaptation to stressful environments. To examine this issue, we have integrated transcriptomics and proteomics data on three human bacterial pathogens: Salmonella enterica Typhimurium, Yersinia pseudotuberculosis, and Staphylococcus aureus under 10 infection-relevant stress conditions. We observed positive correlations between mRNA and protein levels, which were decreased under different stress conditions. Essential genes exhibited higher expression levels with lower variation across the conditions and stronger mRNA-protein correlations compared to nonessential genes, highlighting their critical role in bacterial adaptability and survival. Moreover, we identified a substantial number of genes with stress-induced noncorrelating mRNA-protein levels, particularly under conditions triggering strong stress responses. Particularly this level was dramatically lowered for osmotic stress-specific genes affected by impaired translational activity under osmotic stress. Our findings highlight the prevalence of noncorrelating mRNA-protein levels and the potential role of posttranslational modifications in modulating protein levels in response to environmental stressors during infection. This study provides a comprehensive framework for integrating transcriptomics and proteomics data and identifies potential gene products that might significantly impact the ability of diverse bacterial pathogens to adapt to hostile infection environments.

RNA, Messenger↗

PubMed2026

DrdR Negatively Modulates the Expression of Flagellar Genes via Interaction With FleQ in Xanthomonas campestris.

Response regulators (RRs) of two-component signalling systems (TCSs) containing tandem receiver (REC) domains are widespread in bacteria, yet their functions and regulatory mechanisms remain poorly understood. In our previous study, DrdR, one such RR in the cruciferous black rot disease pathogen Xanthomonas campestris pv. campestris (Xcc) was demonstrated to positively regulate pilus-dependent motility and negatively regulate flagellum-dependent motility. We showed that DrdR modulates the ATPase activities of pili motor proteins PilT and PilB, thereby enhancing bacterial pilus-dependent swarming motility. However, how DrdR represses flagellar motility remained unknown. Here, we demonstrate that DrdR acts as a transcriptional repressor of flagellar gene expression. We used in vitro and in vivo approaches to identify FleQ, the master transcriptional regulator of flagellar genes, as a novel interaction partner of DrdR. Biochemical analyses revealed that DrdR binding inhibits FleQ's ATPase activity, which is essential for its transcriptional activation function. Microscale thermophoresis assays showed that DrdR reduces FleQ's DNA-binding capability to its cognate promoter. These findings collectively indicate that DrdR modulates FleQ transcriptional activity by reducing both its DNA-binding ability and ATPase activity. Our results demonstrate that DrdR serves as a specialized modulator of FleQ that acts upstream in the signalling cascade controlling the expression of flagellar genes in Xcc. This study exhibits a previously unknown mechanism whereby DrdR regulates bacterial motility. Combined with our previous finding, our data suggest that DrdR most likely acts as a conversion regulator between flagellum-dependent and pilus-dependent motility in Xcc.

Flagella↗