Ligand interaction landscape of transcription factors and essential enzymes in E. coli.

Knowledge of protein-metabolite interactions can enhance mechanistic understanding and chemical probing of biochemical processes, but the discovery of endogenous ligands remains challenging. Here, we combined rapid affinity purification with precision mass spectrometry and high-resolution molecular docking to precisely map the physical associations of 296 chemically diverse small-molecule metabolite ligands with 69 distinct essential enzymes and 45 transcription factors in the gram-negative bacterium Escherichia coli. We then conducted systematic metabolic pathway integration, pan-microbial evolutionary projections, and independent in-depth biophysical characterization experiments to define the functional significance of ligand interfaces.

CyuR is a dual regulator for L-cysteine dependent antimicrobial resistance in Escherichia coli.

Hydrogen sulfide (HS), mainly produced from L-cysteine (Cys), renders bacteria highly resistant to oxidative stress and potentially increases antimicrobial resistance (AMR). CyuR is a Cys-dependent transcription regulator, responsible for the activation of the cyuPA operon and generation of HS. Despite its potential importance, its regulatory network remains poorly understood.

CyuR is a Dual Regulator for L-Cysteine Dependent Antimicrobial Resistance in .

Hydrogen sulfide (H S), mainly produced from L-cysteine (Cys), renders bacteria highly resistant to oxidative stress. This mitigation of oxidative stress was suggested to be an important survival mechanism to achieve antimicrobial resistance (AMR) in many pathogenic bacteria. CyuR (known as DecR or YbaO) is a recently characterized Cys-dependent transcription regulator, responsible for the activation of the operon and generation of hydrogen sulfide from Cys.

E. coli allantoinase is activated by the downstream metabolic enzyme, glycerate kinase, and stabilizes the putative allantoin transporter by direct binding.

Allantoin is a good source of ammonium for many organisms, and in Escherichia coli it is utilized under anaerobic conditions. We provide evidence that allantoinase (AllB) is allosterically activated by direct binding of the allantoin catabolic enzyme, glycerate 2-kinase (GlxK) in the presence of glyoxylate. Glyoxylate is known to be an effector of the AllR repressor which regulates the allantoin utilization operons in E.

Evolution of transcriptional regulation of histidine metabolism in Gram-positive bacteria.

Background: The histidine metabolism and transport (his) genes are controlled by a variety of RNA-dependent regulatory systems among diverse taxonomic groups of bacteria including T-box riboswitches in Firmicutes and Actinobacteria and RNA attenuators in Proteobacteria. Using a comparative genomic approach, we previously identified a novel DNA-binding transcription factor (named HisR) that controls the histidine metabolism genes in diverse Gram-positive bacteria from the Firmicutes phylum.

Results: Here we report the identification of HisR-binding sites within the regulatory regions of the histidine metabolism and transport genes in 395 genomes representing the Bacilli, Clostridia, Negativicutes, and Tissierellia classes of Firmicutes, as well as in 97 other HisR-encoding genomes from the Actinobacteria, Proteobacteria, and Synergistetes phyla.