Search results for "plasma protein"
showing 10 items of 193 documents
Temperature‐Responsive Nanoparticles Enable Specific Binding of Apolipoproteins from Human Plasma
2021
Apolipoproteins are an important class of proteins because they provide a so-called stealth effect to nanoparticles. The stealth effect on nanocarriers leads to a reduced unspecific uptake into immune cells and thereby to a prolonged blood circulation time. Herein, a novel strategy to bind apolipoproteins specifically on nanoparticles by adjusting the temperature during their incubation in human plasma is presented. This specific binding, in turn, allows a control of the stealth behavior of the nanoparticles. Nanoparticles with a well-defined poly(N-isopropylacrylamide) shell are prepared, displaying a reversible change of hydrophobicity at a temperature around 32 °C. It is shown by label-f…
�ber die Bedeutung der Plasmaproteinbindung f�r Verteilung und Wirkung von Tranquillantien vom Benzodiazepintyp
1977
This paper discusses the problem if the plasma protein binding of benzodiazepine derivatives can influence distribution and pharmacological activity of the drugs. The distribution of the benzodiazepines in the organism is influenced not only by the plasma protein binding of the drugs, but also by several other factors, especially since the drugs are mostly lipophilic. Thus, an effect of the plasma protein binding on the distribution can only be expected if the benzodiazepine derivative is highly bound to the plasma proteins. Thus results have been shown only for diazepam and chlordiazepoxid, which indicate an effect of the plasma protein binding on distribution and pharmacological activity,…
BBE31 from the Lyme disease agent Borrelia burgdorferi, known to play an important role in successful colonization of the mammalian host, shows the a…
2019
Abstract Lyme disease is a tick-borne infection caused by Borrelia burgdorferi sensu lato complex spirochetes. The spirochete is located in the gut of the tick; as the infected tick starts the blood meal, the spirochete must travel through the hemolymph to the salivary glands, where it can spread to and infect the new host organism. In this study, we determined the crystal structures of the key outer surface protein BBE31 from B. burgdorferi and its orthologous protein BSE31 (BSPA14S_RS05060 gene product) from B. spielmanii. BBE31 is known to be important for the transfer of B. burgdorferi from the gut to the hemolymph in the tick after a tick bite. While BBE31 exerts its function by intera…
Specific binding of Bacillus thuringiensis Cry2A insecticidal proteins to a common site in the midgut of Helicoverpa species
2008
ABSTRACT For a long time, it has been assumed that the mode of action of Cry2A toxins was unique and different from that of other three-domain Cry toxins due to their apparent nonspecific and unsaturable binding to an unlimited number of receptors. However, based on the homology of the tertiary structure among three-domain Cry toxins, similar modes of action for all of them are expected. To confirm this hypothesis, binding assays were carried out with 125 I-labeled Cry2Ab. Saturation assays showed that Cry2Ab binds in a specific and saturable manner to brush border membrane vesicles (BBMVs) of Helicoverpa armigera . Homologous-competition assays with 125 I-Cry2Ab demonstrated that this toxi…
Interaction of Bacillus thuringiensis Cry1 and Vip3A Proteins with Spodoptera frugiperda Midgut Binding Sites
2009
ABSTRACT Vip3Aa, Vip3Af, Cry1Ab, and Cry1Fa were tested for their toxicities and binding interactions. Vip3A proteins were more toxic than Cry1 proteins. Binding assays showed independent specific binding sites for Cry1 and Vip3A proteins. Cry1Ab and Cry1Fa competed for the same binding sites, whereas Vip3Aa competed for those of Vip3Af.
Mutation of the important Tyr-33 residue of chicken avidin: functional and structural consequences
2002
The strong interaction between avidin and biotin is so tight (dissociation constant 10-15M) that conditions usually sufficient for protein denaturing fail to dislodge biotin from the avidin—biotin complex. This kind of irreversible binding hinders the use of avidin in applications such as affinity purification or protein immobilization. To address this concern, we have constructed a series of mutants of the strategically positioned Tyr-33 in order to study the role of this residue in biotin binding, and to create avidin variants with more reversible ligand-binding properties. Unexpectedly, an avidin mutant in which Tyr-33 was replaced with phenylalanine (Avm-Y33F) displayed similar biotin-b…
Cloning and characterization of Scavidin, a fusion protein for the targeted delivery of biotinylated molecules.
2001
We have constructed a novel fusion protein "Scavidin" consisting of the macrophage scavenger receptor class A and avidin. The Scavidin fusion protein is transported to plasma membranes where the avidin portion of the fusion protein binds biotin with high affinity and forms the basis for the targeted delivery of biotinylated molecules. Subcellular fractionation analysis, immunostaining, and electron microscopy demonstrated endosomal localization of the fusion protein. According to pulse-labeling and cross-linking studies Scavidin is found as monomers (55 kDa), dimers, and multimers, of which the 220-kDa form was the most abundant. The biotin binding capacity and active endocytosis of the bio…
Reaggregation and binding of cell wall proteins from Candida albicans to structural polysaccharides
1998
Urea or hot sodium dodecyl sulphate extracted a significant amount of the same proteins from the matrix of the cell wall of the yeast form and mycelial cells of Candida albicans. Gel filtration analysis of the urea-extracted proteins revealed that they occurred in the form of large complexes which were unaffected by up to 8 M urea. Among them, proteins en route to becoming covalently associated within the wall scaffold were identified by their reaction with specific antibodies. When urea was removed by dialysis, some of these proteins specifically reassociated into large aggregates which bound strongly with ConA, whereas others remained soluble in smaller associated products. The ability of…
Streptolysin O: the C-terminal, tryptophan-rich domain carries functional sites for both membrane binding and self-interaction but not for stable oli…
2001
AbstractStreptolysin O belongs to the class of thiol-activated toxins, which are single chain, four-domain proteins that bind to membranes containing cholesterol and then assemble to form large oligomeric pores. Membrane binding involves a conserved tryptophan-rich sequence motif located within the C-terminally located domain 4. In contrast, sites involved in oligomerization and pore formation have been assigned to domains 1 and 3, respectively. We here examined the functional properties of domain 4, which was recombinantly expressed with an N-terminal histidine tag for purification and an additional cysteine residue for covalent labeling. The fluorescently labeled fragment readily bound to…
Triazolopyridyl ketones as a novel class of antileishmanial agents. DNA binding and BSA interaction
2014
A new series of triazolopyridyl pyridyl ketones has been synthetized by regioselective lithiation of the corresponding [1,2,3]triazolo[1,5-a]pyridine at 7 position followed by reaction with different electrophiles. The in vitro antileishmanial activity of these compounds was evaluated against Leishmaniainfantum, Leishmaniabraziliensis, Leishmaniaguyanensis and Leishmaniaamazonensis. Compounds 6 and 7 were found to be the most active leishmanicidal agents. Both of them showed activities at micromolar concentration against cultured promastigotes of Leishmania spp. (IC₅₀=99.8-26.8 μM), without cytotoxicity on J774 macrophage cells. These two compounds were also tested in vivo in a murine model…