Search results for "Binding sites"
showing 10 items of 636 documents
Identification and Characterization of a Single High-Affinity Fatty Acid Binding Site in Human Serum Albumin.
2017
A single high-affinity fatty acid binding site in the important human transport protein serum albumin (HSA) is identified and characterized using an NBD (7-nitrobenz-2-oxa-1,3-diazol-4-yl)-C12 fatty acid. This ligand exhibits a 1:1 binding stoichiometry in its HSA complex with high site-specificity. The complex dissociation constant is determined by titration experiments as well as radioactive equilibrium dialysis. Competition experiments with the known HSA-binding drugs warfarin and ibuprofen confirm the new binding site to be different from Sudlow-sites I and II. These binding studies are extended to other albumin binders and fatty acid derivatives. Furthermore an X-ray crystal structure …
Stability of a Split Streptomycin Binding Aptamer
2016
Here we investigated the stability of an aptamer, which is formed by two RNA strands and binds the antibiotic streptomycin. Molecular dynamics simulations in aqueous solution confirmed the geometry and the pattern of hydrogen bond interactions that was derived from the crystal structure (1NTB). The result of umbrella sampling simulations indicated a favored streptomycin binding with a free energy of ΔGbind° = −101.7 kJ mol–1. Experimentally, the increase in oligonucleotide stability upon binding of streptomycin was probed by single-molecule force spectroscopy. Rate dependent force spectroscopy measurements revealed a decrease in the natural off-rate (koff-COMPLEX = 0.22 ± 0.16 s–1) for the …
Efficacy and Resistance Management Potential of a Modified Vip3C Protein for Control of Spodoptera frugiperda in Maize
2018
AbstractA modified Vip3C protein has been developed that has a spectrum of activity that has the potential to be commercially useful for pest control, and shows good efficacy against Spodoptera frugiperda in insect bioassays and field trials. For the first time Vip3A and Vip3C proteins have been compared to Cry1 and Cry2 proteins in a complete set of experiments from insect bioassays to competition binding assays to field trials, and the results of these complementary experiments are in agreement with each other. Binding assays with radiolabelled toxins and brush border membrane vesicles from S. frugiperda and Helicoverpa armigera show that the modified Vip3C protein shares binding sites wi…
A receptor-antibody hybrid hampering MET-driven metastatic spread
2021
AbstractBackgroundThe receptor encoded by the MET oncogene and its ligand Hepatocyte Growth Factor (HGF) are at the core of the invasive-metastatic behavior. In a number of instances genetic alterations result in ligand-independent onset of malignancy (METaddiction). More frequently, ligand stimulation of wild-type MET contributes to progression toward metastasis (METexpedience). Thus, while MET inhibitors alone are effective in the first case, combination therapy with ligand inhibitors is required in the second condition.MethodsIn this paper, we generated hybrid molecules gathering HGF and MET inhibitory properties. This has been achieved by ‘head-to-tail’ or ‘tail-to-head’ fusion of a sin…
Improved display of synthetic IgG-binding domains on the baculovirus surface.
2004
Improved display of foreign protein moieties in combination with beneficial alteration of the viral surface properties should be of value for targeted and enhanced gene delivery. Here, we describe a vector based on Autographa californica multiple nucleopolyhedrovirus (AcMNPV) displaying synthetic IgG-binding domains (ZZ) of protein A fused to the transmembrane anchor of vesicular stomatitis virus (VSV) G protein. This display vector was equipped with a GFP/EGFP expression cassette enabling fluorescent detection in both insect and mammalian cells. The virus construct displayed the biologically active fusion protein efficiently and showed increased binding capacity to IgG. As the display is …
Hetero-oligomerization of Bacillus thuringiensis Cry1A proteins enhance binding to the ABCC2 transporter of Spodoptera exigua
2021
The ATP binding cassette (ABC) transporters are membrane proteins that can act as putative receptors for Cry proteins from Bacillus thuringiensis (Bt) in the midgut of different insects. For the beet armyworm, Spodoptera exigua, ABCC2 and ABCC3 have been found to interact with Cry1A proteins, the main insecticidal proteins used in Bt crops, as well as Bt-based pesticides. The ABCC2 has shown to have specific binding towards Cry1Ac and is involved in the toxic process of Cry1A proteins, but the role of this transporter and how it relates with the Cry1A proteins is still unknown. Here, we have characterized the interactions between the SeABCC2 and the main proteins that bind to the receptor. …
New insights into the mechanism of action of pyrazolo[1,2-a]benzo[1,2,3,4]tetrazin-3-one derivatives endowed with anticancer potential
2018
Due to the scarce biological profile, the pyrazolo[1,2-a]benzo[1,2,3,4]tetrazine-3-one scaffold (PBT) has been recently explored as promising core for potential anticancer candidates. Several suitably decorated derivatives (PBTs) exhibited antiproliferative activity in the low-micromolar range associated with apoptosis induction and cell cycle arrest on S phase. Herein, we selected the most active derivatives and submitted them to further biological explorations to deepen the mechanism of action. At first, a DNA targeting is approached by means of flow Linear Dichroism experiments so as to evaluate how small planar molecules might interact with DNA, including the interference with the catal…
Design, synthesis, and biological evaluation of a new class of benzo[b]furan derivatives as antiproliferative agents, with in silico predicted antitu…
2018
A new series of 3-benzoylamino-5-(1H-imidazol-4-yl)methylaminobenzo[b]furans were synthesized and screened as antitumor agents. As a general trend, tested compounds showed concentration-dependent antiproliferative activity against HeLa and MCF-7 cancer cell lines, exhibiting GI50 values in the low micromolar range. In most cases, insertion of a methyl substituent on the imidazole moiety improved the antiproliferative activity. Therefore, methyl-imidazolyl-benzo[b]furans compounds were tested in cell cycle perturbation experiments, producing cell cycle arrest with proapoptotic effects. Their core similarity to known colchicine binding site binders led us to further study the structure featur…
Identification of the integrin-binding site on coagulation factor VIIa required for proangiogenic PAR2 signaling.
2018
The tissue factor (TF) pathway serves both hemostasis and cell signaling, but how cells control these divergent functions of TF remains incompletely understood. TF is the receptor and scaffold of coagulation proteases cleaving protease-activated receptor 2 (PAR2) that plays pivotal roles in angiogenesis and tumor development. Here we demonstrate that coagulation factor VIIa (FVIIa) elicits TF cytoplasmic domain-dependent proangiogenic cell signaling independent of the alternative PAR2 activator matriptase. We identify a Lys-Gly-Glu (KGE) integrin-binding motif in the FVIIa protease domain that is required for association of the TF-FVIIa complex with the active conformer of integrin β1. A po…
Alkaline phosphatase dual-binding sites for collagen dictate cell migration and microvessel assembly in vitro
2020
Interactions between cell types, growth factors, and extracellular matrix components involved in angiogenesis are crucial for new vessel formation leading to tissue regeneration. This study investigated whether cocultures of fibroblasts and endothelial cells (ECs; from macro- or microvasculature) play a role in the formation of microvessel-like structures by ECs, as well as modulate fibroblast differentiation and growth factors production (vascular endothelial cell growth factor, basic fibroblast growth factor, active transforming growth factor-beta 1, and interleukin-8), which are important for vessel sprouting and maturation. Data obtained revealed that in vitro coculture systems of fibro…