Structural and biophysical characterization of the cytoplasmic domains of HprS kinase and its interactions with the cognate regulator HprR.

The HprSR constitutes the bacterial two-component regulatory system engaged by Escherichia coli to reduce the damaging effects of reactive chlorine and oxygen species present in its cytosol. Hypochlorous acid (HOCl) has been shown to be the molecule capable of activating of the HprSR system. HOCl is produced upon pathogen invasion by phagocytic cells of the human innate immune system, particularly neutrophils, to take advantage of its powerful antimicrobial attributes.

Arabidopsis thaliana argininosuccinate lyase structure uncovers the role of serine as the catalytic base.

Arginine is an important amino acid in plants, as it not only plays a structural role and serves as nitrogen storage but is also a precursor for various molecules, including polyamines and proline. Arginine is produced by argininosuccinate lyase (ASL) which catalyzes the cleavage of argininosuccinate to arginine and fumarate. ASL belongs to the fumarate lyase family and while many members of this family were well-characterized, little is known about plant ASLs.

Stapled peptides as potential therapeutics for diabetes and other metabolic diseases.

The field of peptide drug research has experienced notable progress, with stapled peptides featuring stabilized α-helical conformation, emerging as a promising field. These peptides offer enhanced stability, cellular permeability, and binding affinity and exhibit potential in the treatment of diabetes and metabolic disorders. Stapled peptides, through the disruption of protein-protein interactions, present varied functionalities encompassing agonism, antagonism, and dual-agonism.

Comprehensive structural overview of the C-terminal ligand-binding domains of the TetR family regulators.

TetR family regulators (TFRs) represent a large group of one-component bacterial signal transduction systems which recognize environmental signals, like the presence of antibiotics or other bactericidal compounds, and trigger the cell response by regulating the expression of genes that secure bacterial survival in harsh environmental conditions. TFRs act as homodimers, each protomer is composed of a conserved DNA-binding N-terminal domain (NTD) and a variable ligand-binding C-terminal domain (CTD). Currently, there are about 500 structures of TFRs available in the Protein Data Bank and one-fourth of them represent the structures of TFR-ligand complexes.

Structural analysis and molecular substrate recognition properties of ornithine transcarbamylase, the molecular target of phaseolotoxin produced by .

Halo blight is a plant disease that leads to a significant decrease in the yield of common bean crops and kiwi fruits. The infection is caused by pathovars that produce phaseolotoxin, an antimetabolite which targets arginine metabolism, particularly by inhibition of ornithine transcarbamylase (OTC). OTC is responsible for production of citrulline from ornithine and carbamoyl phosphate.

Crystal structure of the Escherichia coli CusS kinase core.

The CusS histidine kinase is a member of Escherichia coli two-component signal transduction system, engaged in a response to copper ions excess in the cell periplasm. The periplasmic sensor domain of CusS binds the free copper ions and the CusS kinase core phosphorylates the cognate CusR which regulates transcription of the efflux pomp CusCBA. A small amount of copper ions is indispensable for the aerobic cell metabolism.

Characterization of the Putative Acylated Cellulose Synthase Operon in E25.

Bacterial cellulose is a natural polymer with an expanding array of applications. Because of this, the main cellulose producers of the genus have been extensively studied with the aim to increase its synthesis or to customize its physicochemical features. Up to now, the genetic studies in have focused on the first cellulose synthase operon () encoding the main enzyme complex.

Structures of the TetR-like transcription regulator RcdA alone and in complexes with ligands.

RcdA is a helix-turn-helix (HTH) transcriptional regulator belonging to the TetR family. The protein regulates the transcription of curlin subunit gene D, the master regulator of biofilm formation. Moreover, it was predicted that it might be involved in the regulation of up to 27 different genes.

Structural Evidence of Active Site Adaptability towards Different Sized Substrates of Aromatic Amino Acid Aminotransferase from Sp. B6.

Aromatic amino acid aminotransferases present a special potential in the production of drugs and synthons, thanks to their ability to accommodate a wider range of substrates in their active site, in contrast to aliphatic amino acid aminotransferases. The mechanism of active site adjustment toward substrates of psychrophilic aromatic amino acid aminotransferase (ArAT) from sp. B6 is discussed based on crystal structures of complexes with four hydroxy-analogs of substrates: phenylalanine, tyrosine, tryptophan and aspartic acid.

The interaction of DNA repair factors ASCC2 and ASCC3 is affected by somatic cancer mutations.

The ASCC3 subunit of the activating signal co-integrator complex is a dual-cassette Ski2-like nucleic acid helicase that provides single-stranded DNA for alkylation damage repair by the α-ketoglutarate-dependent dioxygenase AlkBH3. Other ASCC components integrate ASCC3/AlkBH3 into a complex DNA repair pathway. We mapped and structurally analyzed interacting ASCC2 and ASCC3 regions.

H-type lectins - Structural characteristics and their applications in diagnostics, analytics and drug delivery.

Lectins are ubiquitous carbohydrate-binding proteins that interact with sugar moieties in a highly specific manner. H-type lectins represent a new group of lectins that were identified in invertebrates. These lectins share structural homology and bind mainly to N-acetylgalactosamine (GalNAc).

Redox regulation by reversible protein S-thiolation in Gram-positive bacteria.

Low molecular weight (LMW) thiols play an important role as thiol-cofactors for many enzymes and are crucial to maintain the reduced state of the cytoplasm. Most Gram-negative bacteria utilize glutathione (GSH) as major LMW thiol. However, in Gram-positive Actinomycetes and Firmicutes alternative LMW thiols, such as mycothiol (MSH) and bacillithiol (BSH) play related roles as GSH surrogates, respectively.

Crystal Structure of the Escherichia coli DExH-Box NTPase HrpB.

Eukaryotic DExH-box proteins are important post-transcriptional gene regulators, many of which employ RNA-stimulated nucleoside triphosphatase activity to remodel RNAs or ribonucleoprotein complexes. However, bacterial DExH-box proteins are structurally and functionally poorly characterized. We report the crystal structure of the Escherichia coli DExH-box protein HrpB.

The aldehyde dehydrogenase AldA contributes to the hypochlorite defense and is redox-controlled by protein S-bacillithiolation in Staphylococcus aureus.

Staphylococcus aureus produces bacillithiol (BSH) as major low molecular weight (LMW) thiol which functions in thiol-protection and redox-regulation by protein S-bacillithiolation under hypochlorite stress. The aldehyde dehydrogenase AldA was identified as S-bacillithiolated at its active site Cys279 under NaOCl stress in S. aureus.

Crystal structures of serum albumins from domesticated ruminants and their complexes with 3,5-diiodosalicylic acid.

Serum albumin (SA) is the most abundant protein in plasma and is the main transporter of molecules in the circulatory system of all vertebrates, with applications in medicine, the pharmaceutical industry and molecular biology. It is known that albumins from different organisms vary in sequence; thus, it is important to know the impact of the amino-acid sequence on the three-dimensional structure and ligand-binding properties. Here, crystal structures of ovine (OSA) and caprine (CSA) serum albumins, isolated from sheep and goat blood, are described, as well those of their complexes with 3,5-diiodosalicylic acid (DIS): OSA-DIS (2.

Protein S-Bacillithiolation Functions in Thiol Protection and Redox Regulation of the Glyceraldehyde-3-Phosphate Dehydrogenase Gap in Staphylococcus aureus Under Hypochlorite Stress.

Aims: Bacillithiol (BSH) is the major low-molecular-weight thiol of the human pathogen Staphylococcus aureus. In this study, we used OxICAT and Voronoi redox treemaps to quantify hypochlorite-sensitive protein thiols in S. aureus USA300 and analyzed the role of BSH in protein S-bacillithiolation.

Structural studies of a cold-adapted dimeric β-D-galactosidase from Paracoccus sp. 32d.

The crystal structure of a novel dimeric β-D-galactosidase from Paracoccus sp. 32d (ParβDG) was solved in space group P212121 at a resolution of 2.4 Å by molecular replacement with multiple models using the BALBES software.