Streptavidin-biotin interactions

Covalent attachment of enzymes to surfaces is often intuitively perceived as being more reliable than direct adsorption, but multisite physical interactions can in fact yield a comparably strong and stable union, as demonstrated by several biological examples. The biotin/streptavidin interaction requires a force of about 0.3 nN to be severed [Lee et al., 2007], and protein/protein interactions typically require 0.1 nN to break, but values over 1 nN have also been reported [Weisel et al., 2003]. These forces are comparable to those required to mpture weaker chemical bonds such as the gold-thiolate bond (1 nN for an alkanethiol, and even only 0.3 nN for a 1,3-aUcanedithiol [Langry et al., 2005]) and the poly(His)-Ni(NTA) bond (0.24 nN, [Levy and Maaloum, 2005]). 

FIGURE 5.5 Schematic representations of the two immunosensor formats (a) immunosensor based on the biotin-streptavidin interaction and (b) immunosensor based on rabbit IgG-modified SPCEs. (Reprinted from [27] with permission from Elsevier.)... 

Example 39 biotin is used for DNA detection due to the exceptionally high biotin-streptavidin interaction [72]. Rothschild and associates [73] have reported the synthesis of photocleavable biotin phosphoroamidite employing 2-cyanoethyl-iV,Ar-diisopropylchlorophosphoroamidite. 

Jung YK, Park HG, Kim JM. Polydiacetylene (PDA)-based colorimetric detection of biotin-streptavidin interactions. Biosens Bioelectron 2006 21 1536-1544. 

Figure 26. Schematic of the post hybridization detection method. A DNA target solution labeled with biotin is first incubated with the DNA probe functionalized chip. Targets diffuse passively from the solution to the surface where they hybridized with the probes if complementary. A solution containing streptavidin-functionalized magnetic labels is then incubated with the chip. Labels bind through the biotin-streptavidin interaction to where hybridization occurred. DNA hybridization is detected with spintronic transducers.

Alternatively, biopanning on plates is based on the strong biotin-streptavidin interaction to isolate target-binding phages [6]. Figure 19.4 shows a schematic representation of the procedure. 

FIGURE 19.4 Biopanning selection through biotin-streptavidin interaction. The library is incubated with the biotinylated target in solution phages displaying the active binding peptide are captured on a streptavidin-coated Petri dish, eluted, and amplified. 

Fig. 11. A layer-by-layer model built by biotin-streptavidin interaction. (A) Angular SPR curves of each layer. The inset shows the SPR minimum position as a function of layer number. (B) SPR, fluorescence angular scans for layers a , b , i , and j .

The availability of a new version of isotopically labeled ATP, [33P]ATP, provided benefits of safety and longer half-life. The lowered energy was also better suited for scintillation proximity assays (SPAs). The SPA was a major step forward because it eliminated the need for wash steps by capturing the [33P]-labeled peptide on a functionalized scintillating crystal, usually via a biotin-streptavidin interaction. 

Why did the authors not use the anti - S-N=0 antibody instead Maybe they didn t think of it. However, I suspect that the antibody might not possess sufficient affinity to allow for stringent washing of blots and columns. The biotin-streptavidin interaction is very stable and thus withstands the stringent washing steps required for selective detection within complex protein mixtures such as whole cell extracts. 

In addition to the general criteria discussed above, each assay technology can also suffer from technology-specific interference of chemical compounds. Auto-fluorescent compounds can interfere with any fluorescence-based readout. In assays that use the biotin-streptavidin interaction, biotin analogs are potential false positives. 

Fig. 4.15. Setup for measuring the turnover of dihydro-rhodamin by horse radish peroxidase bound to a coverslip by biotin-streptavidin interaction...

Whatever the coupling agent is, the control of non-specific protein absorption is important to the use of nanomaterials in specific protein binding. There are plenty of molecules used for protection of various surfaces from proteins with mechanisms as steric repulsion, hydration and solvent structuring. For example, the modification of CNTs with the absorption of biotinylated Tween 20 allowed streptavidin recognition by the specific biotin-streptavidin interaction, but provided resistance towards other protein absorption [133]. 

Method II Indirect binding using biotin-streptavidin interaction. Conjugation of Ru(bpy)32+-COOH to streptavidin. Ru(bpy)32+-COOH was dissolved in DMF to obtain 70 pL of a solution with a concentration of 7.1 10 3 mol/L. 1.5 equivalents of DCC and NHS were added and the reaction solution was gently mixed for 4 h at RT. 630 pL of a 2.0x10 5 mol/L streptavidin solution in 0.1 mol/L borate buffer (pH 9.4) were then added (activated Ru(bpy)32+-COOH streptavidin 40 1 molar ratio). The solution was incubated overnight and the labeled protein was subsequently purified with dialysis against 5 L of PBS. 

Ladd et al. have recently demonstrated the simultaneous detection of three serotypes of EoNT using a custom-built SPR sensor (submitted for publication). Detections of serotypes A, E, and F were done using a sandwich assay with polyclonal antibodies immobilized via biotin-streptavidin interactions. The lowest concentrations detected for serotypes A, E, and F in buffer were 1 ng/mL, 1 ng/mL, and 0.5 ng/mL, respectively. Detections performed in a 20% honey solution showed good agreement with detections performed in buffer. 

Efficient immobilization of aptamers on surfaces is necessary for the construction of tongh, stable sensors and assay systems as one necessary step to overcome limitations for practical applications (Bini et al., 2007). Bini et al. (2007) have compared thrombin aptamers immobilized on a gold snrface by chemisorption (thiolated aptamer) and by biotin-streptavidin interaction (biotinylated aptamer carrying a linker) on a gold surface modified by a thiol-dextran-streptavidin layer. The linker-modified aptamer immobilized via streptavidin-biotin showed better reproducibility and sensitivity results for the quartz crystal sensor. Aptamers can be used for the functionalization of titanium-alloy surfaces (e.g., implant material, scaffolds) to enhance cell adhesion. The aptamers directed to osteoblasts are fixed electrochemically on the snrface of the alloy and promote cell adhesion (Gno et al., 2005, 2007). 

Figure 9.5. Scheme of an assay in which enzyme is incorporated through biotin streptavidin interaction. Reprinted with permission from Elsevier... 

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