Small-molecule AgrA inhibitors F12 and F19 act as antivirulence agents against Gram-positive pathogens.

Small-molecule antivirulence agents represent a promising alternative or adjuvant to antibiotics. These compounds disarm pathogens of disease-causing toxins without killing them, thereby diminishing survival pressure to develop resistance. Here we show that the small-molecule antivirulence agents F12 and F19 block staphylococcal transcription factor AgrA from binding to its promoter.

DAF in diabetic patients is subject to glycation/inactivation at its active site residues.

Decay accelerating factor (DAF or CD55) is a cell associated C3 and C5 convertase regulator originally described in terms of protection of self-cells from systemic complement but now known to modulate adaptive T cell responses. It is expressed on all cell types. We investigated whether nonenzymatic glycation could impair its function and potentially be relevant to complications of diabetes mellitus and other conditions that result in nonenzymatic glycation including cancer, Alzheimer's disease, and aging.

Biofilm inhibitors targeting the outer membrane protein A of Pasteurella multocida in swine.

Pasteurella multocida (Pm) is the causative agent of atrophic rhinitis in swine. This study aimed to discover biofilm inhibitors against swine Pm to counteract antibiotic resistance and decrease virulence. The virulence factor outer membrane protein A (OmpA) was targeted.

AF1q is a novel TCF7 co-factor which activates CD44 and promotes breast cancer metastasis.

AF1q is an MLL fusion partner that was identified from acute myeloid leukemia (AML) patients with t (1; 11) (q21; q23) chromosomal abnormality. The function of AF1q is not yet fully known, however, elevated AF1q expression is associated with poor clinical outcomes in various malignancies. Here, we show that AF1q specifically binds to T-cell-factor-7 (TCF7) in the Wnt signaling pathway and results in transcriptional activation of CD44 as well as multiple downstream targets of the TCF7/LEF1.

Novel quorum-quenching agents promote methicillin-resistant Staphylococcus aureus (MRSA) wound healing and sensitize MRSA to β-lactam antibiotics.

The dwindling repertoire of antibiotics to treat methicillin-resistant Staphylococcus aureus (MRSA) calls for novel treatment options. Quorum-quenching agents offer an alternative or an adjuvant to antibiotic therapy. Three biaryl hydroxyketone compounds discovered previously (F1, F12, and F19; G.

Combinatorial synthesis and in vitro evaluation of a biaryl hydroxyketone library as antivirulence agents against MRSA.

Antibiotic resistance coupled with decreased development of new antibiotics necessitates the search for novel antibacterial agents. Antivirulence agents offer an alternative to conventional antibiotics. In this work, we report on a family of small-molecule antivirulence agents against methicillin-resistant Staphylococcus aureus (MRSA), the most widespread bacterial pathogen.

Discovery of antivirulence agents against methicillin-resistant Staphylococcus aureus.

Antivirulence agents inhibit the production of disease-causing virulence factors but are neither bacteriostatic nor bactericidal. Antivirulence agents against methicillin-resistant Staphylococcus aureus (MRSA) strain USA300, the most widespread community-associated MRSA strain in the United States, were discovered by virtual screening against the response regulator AgrA, which acts as a transcription factor for the expression of several of the most prominent S. aureus toxins and virulence factors involved in pathogenesis.

Fine specificity of Plasmodium vivax Duffy binding protein binding engagement of the Duffy antigen on human erythrocytes.

Plasmodium vivax invasion of human erythrocytes requires interaction of the P. vivax Duffy binding protein (PvDBP) with its host receptor, the Duffy antigen (Fy) on the erythrocyte surface. Consequently, PvDBP is a leading vaccine candidate.

Signal peptide of FadA adhesin from Fusobacterium nucleatum plays a novel structural role by modulating the filament's length and width.

FadA, a novel adhesin of periodontal pathogen Fusobacterium nucleatum is composed of two forms, pre-FadA and mature FadA (mFadA), constituting the functional FadA complex (FadAc). By electron microscopy, we observed that mFadA formed uniformly long and thin filaments, while FadAc formed heterogeneous filaments of varying lengths and widths, as well as "knots". Mutants in signal peptide or in the non-alpha-helical loop retaining heterogeneous structures had binding activity while those forming aggregates or long filaments lost activity.

Fusobacterium nucleatum adhesin FadA binds vascular endothelial cadherin and alters endothelial integrity.

Fusobacterium nucleatum is a Gram-negative oral anaerobe, capable of systemic dissemination causing infections and abscesses, often in mixed-species, at different body sites. We have shown previously that F. nucleatum adheres to and invades host epithelial and endothelial cells via a novel FadA adhesin.

Tyrosine sulfation: an increasingly recognised post-translational modification of secreted proteins.

The post-translational sulfation of tyrosine residues occurs in numerous secreted and integral membrane proteins and, in many cases, plays a crucial role in controlling the interactions of these proteins with physiological binding partners as well as invading pathogens. Recent advances in our understanding of protein tyrosine sulfation have come about owing to the cloning of two human tyrosylprotein sulfotransferases (TPST-1 and TPST-2), the development of novel analytical and synthetic methodologies and detailed studies of proteins and peptides containing sulfotyrosine residues. In this article, we describe the TPST enzymes, review the major techniques available for studying the presence, location and function of tyrosine sulfation in proteins and discuss the biological functions and biochemical interactions of several proteins (or protein families) in which tyrosine sulfation influences the protein function.

Crystal structure of FadA adhesin from Fusobacterium nucleatum reveals a novel oligomerization motif, the leucine chain.

Many bacterial appendages have filamentous structures, often composed of repeating monomers assembled in a head-to-tail manner. The mechanisms of such linkages vary. We report here a novel protein oligomerization motif identified in the FadA adhesin from the Gram-negative bacterium Fusobacterium nucleatum.

Discovery of a quorum-sensing inhibitor of drug-resistant staphylococcal infections by structure-based virtual screening.

Staphylococci are a major health threat because of increasing resistance to antibiotics. An alternative to antibiotic treatment is preventing virulence by inhibition of bacterial cell-to-cell communication using the quorum-sensing inhibitor RNAIII-inhibiting peptide (RIP). In this work, we identified 2',5-di-O-galloyl-d-hamamelose (hamamelitannin) as a nonpeptide analog of RIP by virtual screening of a RIP-based pharmacophore against a database of commercially available small-molecule compounds.

Crystallization and preliminary X-ray data of the FadA adhesin from Fusobacterium nucleatum.

Fusobacterium nucleatum is a gram-negative anaerobe prevalent in the oral cavity that is associated with periodontal disease, preterm birth and infections in other parts of the human body. The bacteria attach to and invade epithelial and endothelial cells in the gum tissue and elsewhere via a 13.7 kDa adhesin protein FadA (Fusobacterium adhesin A).

Arrestin binding to calmodulin: a direct interaction between two ubiquitous signaling proteins.

Arrestins serve as multi-functional regulators of G-protein coupled receptors, interacting with hundreds of different receptor subtypes and a variety of other signaling proteins. Here we identify calmodulin as a novel arrestin interaction partner using three independent methods in vitro and in cells. Arrestin preferentially binds calcium-loaded calmodulin with a Kd value of approximately 7 microM, which is within range of endogenous calmodulin concentrations.

Soluble mimics of the cytoplasmic face of the human V1-vascular vasopressin receptor bind arrestin2 and calmodulin.

Signal transduction by G protein-coupled receptors (GPCRs) is mediated by interactions between intracellular proteins and exposed motifs on the cytoplasmic face of these receptors. Arrestins bind to GPCRs and modulate receptor function either by interfering with heterotrimeric G protein signaling or by serving as signaling adaptors themselves. Calmodulin interacts with GPCRs triggering a calcium response.

A C-terminal segment of the V1R vasopressin receptor is unstructured in the crystal structure of its chimera with the maltose-binding protein.

The V1 vascular vasopressin receptor (V1R) is a G-protein-coupled receptor (GPCR) involved in the regulation of body-fluid osmolality, blood volume and blood pressure. Signal transduction is mediated by the third intracellular loop of this seven-transmembrane protein as well as by the C-terminal cytoplasmic segment. A chimera of the maltose-binding protein (MBP) and the C-terminal segment of V1R has been cloned, expressed, purified and crystallized.

Mapping the binding site of six nonpeptide antagonists to the human V2-renal vasopressin receptor.

Whereas arginine vasopressin binds to its receptor subtypes V(1)R and V(2)R with equal affinity of approximately 2 nM, nonpeptide antagonists interact differently with vasopressin receptor subtypes. The V(2)R antagonist binding site was mapped by site-directed mutagenesis at six selected amino acid positions, K100D, A110W, M120V, L175Y, R202S, and F307I, predicted to be involved in antagonist binding differences between V(2) R and V(1)R. These mutations did not alter the affinity for arginine vasopressin.

Prediction of the structure of the complex between the 30S ribosomal subunit and colicin E3 via weighted-geometric docking.

Colicin E3 kills Escherichia coli cells by ribonucleolytic cleavage in the 16S rRNA. The cleavage occurs at the ribosomal decoding A-site between nucleotides A1493 and G1494. The breaking of this single phosphodiester bond results in a complete termination of protein biosynthesis leading to cell death.

On the interaction of colicin E3 with the ribosome.

Colicin E3 is a protein that kills Escherichia coli cells by a process that involves binding to a surface receptor, entering the cell and inactivating its protein biosynthetic machinery. Colicin E3 kills cells by a catalytic mechanism of a specific ribonucleolytic cleavage in 16S rRNA at the ribosomal decoding A-site between A1493 and G1494 (E. coli numbering system).

Structure of decay-accelerating factor bound to echovirus 7: a virus-receptor complex.

Echoviruses are enteroviruses that belong to Picornaviridae. Many echoviruses use decay-accelerating factor (DAF) as their cellular receptor. DAF is a glycosylphosphatidyl inositol-anchored complement regulatory protein found on most cell surfaces.