Search results for "Avidin"
showing 10 items of 97 documents
Interaction between biotin lipids and streptavidin in monolayers: formation of oriented two-dimensional protein domains induced by surface recognitio…
1989
Highly specific ligand-receptor interactions generally characterize surface recognition reactions. Such processes can be simulated by streptavidin-biotin-specific binding. Biotin lipids have thus been synthesized, and their interaction with streptavidin (or avidin) at the air-water interface was directly shown by measurement of surface pressure isotherms and fluorescence microscopy. These proteins interact with the biotin lipid monolayer via specific binding or nonspecific adsorption. Both phenomena were clearly distinguished by use of the inactivated form of streptavidin. The binding of fluorescein-labeled streptavidin to monolayers was also directly observed by fluorescence microscopy. Th…
Molecular recognition processes at functionalized lipid surfaces: a neutron reflectivity study
1992
The specific binding of proteins to functionalized monolayers on aqueous subphases has been characterized by neutron reflectivity measurements. As a model for the investigation of a recognition process on a molecular length scale, streptavidin (SA) and biotin were chosen because of the high specific affinity between them. Reflectivities from the aqueous (NaCl/H2O or NaCl/D2O) surfaces covered with the biotin-lipid monolayers before and after the adsorption of proteins were collected with a novel, fixed wavelength liquid surface neutron reflectometer. In quantitative terms, binding was found to occur at a biotin surface concentration as low as 1 molecule/1250 A2 (compare to ∼ 1 molecule/40 A…
(Strept)avidin as host for biotinylated coordination complexes: stability, chiral discrimination, and cooperativity
2005
Incorporation of a biotinylated ruthenium tris(bipyridine) [Ru(bpy)₂(Biot-bpy)]²⁺ (1) in either avidin or streptavidin-(strept)avidin-can be conveniently followed by circular dichroism spectroscopy. To determine the stepwise association constants, cooperativity, and chiral discrimination properties, diastereopure (Λ and δ)-1 species were synthesized and incorporated in tetrameric (strept)avidin to afford (δ-[Ru(bpy)₂(Biot-bpy)]²⁺)x⊂avidin, (Λ- [Ru(bpy)₂(Biot-bpy)]²⁺)x⊂avidin, (δ-[Ru(bpy)₂(Biot- bpy)]²⁺)x⊂streptavidin, and (Λ-[Ru(bpy)₂(Biot-bpy)]²⁺) x⊂streptavidin (x = 1-4) For these four systems, the overall stability constants are log β₄ = 28.6, 30.3, 36.2, and 36.4, respectively. Critical…
Adsorption and Conformation Behavior of Biotinylated Fibronectin on Streptavidin-Modified TiOX Surfaces Studied by SPR and AFM
2011
It is well-known that protein-modified implant surfaces such as TiO(2) show a higher bioconductivity. Fibronectin is a glycoprotein from the extracellular matrix (ECM) with a major role in cell adhesion. It can be applied on titanium oxide surfaces to accelerate implant integration. Not only the surface concentration but also the presentation of the protein plays an important role for the cellular response. We were able to show that TiO(X) surfaces modified with biotinylated fibronectin adsorbed on a streptavidin-silane self-assembly multilayer system are more effective regarding osteoblast adhesion than surfaces modified with nonspecifically bound fibronectin. The adsorption and conformati…
Engineering of chicken avidin: a progressive series of reduced charge mutants.
1998
Avidin, a positively charged egg-white glycoprotein, is a widely used tool in biotechnological applications because of its ability to bind biotin strongly. The high pI of avidin (approximately 10.5), however, is a hindrance in certain applications due to non-specific (charge-related) binding. Here we report a construction of a series of avidin charge mutants with pIs ranging from 9.4 to 4.7. Rational design of the avidin mutants was based on known crystallographic data together with comparative sequence alignment of avidin, streptavidin and a set of avidin-related genes which occur in the chicken genome. All charge mutants retained the ability to bind biotin tightly according to optical bio…
X-ray diffraction of a protein crystal anchored at the air/water interface
1995
We report the first successful in situ x-ray diffraction experiment with a 2D protein array at the lipid/water interface and demonstrate that the order can be controlled via lateral pressure or density. A protein (streptavidin) was bound to a monolayer of biotinylated lipid at the air/water interface, and diffraction of the protein layer could be measured to many orders. Compression of the monolayer changed the diffraction pattern drastically, indicating that the protein structure can be strongly influenced by external parameters like lateral pressure or density. From the width of the peaks, we find that aggregates consisting of as few as 100 monomers contribute to the diffraction. This ind…
Recombinant NeutraLite Avidin: a non-glycosylated, acidic mutant of chicken avidin that exhibits high affinity for biotin and low non-specific bindin…
2000
AbstractA recombinant non-glycosylated and acidic form of avidin was designed and expressed in soluble form in baculovirus-infected insect cells. The mutations were based on the same principles that guided the design of the chemically and enzymatically modified avidin derivative, known as NeutraLite Avidin. In this novel recombinant avidin derivative, five out of the eight arginine residues were replaced with neutral amino acids, and two of the lysine residues were replaced by glutamic acid. In addition, the carbohydrate-bearing asparagine-17 residue was altered to an isoleucine, according to the known sequences of avidin-related genes. The resultant mutant protein, termed recombinant Neutr…
Characterization of poultry egg-white avidins and their potential as a tool in pretargeting cancer treatment.
2003
Chicken avidin and bacterial streptavidin are proteins used in a wide variety of applications in the life sciences due to their strong affinity for biotin. A new and promising use for them is in medical pretargeting cancer treatments. However, their pharmacokinetics and immunological properties are not always optimal, thereby limiting their use in these applications. To search for potentially beneficial new candidates, we screened egg white from four different poultry species for avidin. Avidin proteins, isolated from the duck, goose, ostrich and turkey, showed a similar tetrameric structure, similar glycosylation and stability against both temperature and proteolytic activity of proteinase…
Recombinant avidin and avidin-fusion proteins.
2000
Both chicken egg-white avidin and its bacterial relative streptavidin are well known for their extraordinary high affinity with biotin (Kd approximately 10(-15) M). They are widely used as tools in a number of affinity-based separations, in diagnostic assays and in a variety of other applications. These methods have collectively become known as (strept)avidin-biotin technology. Biotin can easily and effectively be attached to different molecules, termed binders and probes, without destroying their biological activity. The exceptional stability of the avidin-biotin complex and the wide range of commercially available reagents explain the popularity of this system. In order by genetic enginee…
Formation of protein multilayers and their competitive replacement based on self-assembled biotinylated phospholipids.
1994
Based on specific recognition processes the build-up of protein multilayers was achieved using streptavidin layers as a docking matrix. For this purpose, streptavidin was organized at biotin-containing monolayers, liposomes, and self-assembled layers on gold. Thus, mixed double and triple layers of streptavidin, Con A, Fab fragments, and hormones were prepared and characterized by fluorescence microscopy and plasmon spectroscopy. Using biotin analogues with lower binding constants several cycles of multilayer formation followed by competitive replacement could be achieved.