On the Adsorption Behavior of Biotin-Binding Proteins on Gold and Silica

Abstract

Streptavidin (SAv), avidin (Av), and neutravidin (NAv) have become widely used molecular tools in biotechnology thanks to their remarkable affinity for biotin. Their tetravalency renders these molecules particularly interesting for the functionalization of solid-liquid interfaces. Using the quartz crystal microbalance with dissipation monitoring, we systematically investigate the deposition of biotin-binding proteins to two surfaces that are popular in biotechnology: gold and silica. We find that simple physisorption of biotin-binding proteins is a viable method to confer biotin-binding functionality to gold surfaces. Both SAv and Av form dense, stable protein monolayers that retain biotin-binding activity and are largely inert to the unspecific binding of bovine serum albumin. Furthermore, we report that SAv resists adsorption to silica over a wide range of pH and ionic strength. The contrast in the binding behavior of SAv on silica and on gold suggests a simple strategy for the selective biofunctionalization of nano- or microstructured surfaces.

Transient Exposure of Pulmonary Surfactant to Hyaluronan Promotes Structural and Compositional Transformations into a Highly Active State

“…3, GUVs (31) is characteristic for the formation of a supported lipid bilayer in which vesicles first bind intact and then rupture and spread (56). The monotonous response and saturation for neutravidin is consistent with the formation of a thin protein film (57). Strong dissipation shifts and small frequency shifts upon incubation of end-biotinylated HA reflect the formation of a soft and strongly hydrated HA film (31).…”

Non-specific interactions between soluble proteins and lipids induce irreversible changes in the properties of lipid bilayers

“…These DF and DD values correspond to $50 weight% of a full protein monolayer (of the size of BSA 27 ) on top of the SLB or $77 ng cm À2 based on the Sauerbrey equation (Dm ¼ ÀCDf n /n). 7 For neutral membranes, on the other hand, a more pronounced effect was observed for 1% FBS where a steep increase in DF (À11 to À14 Hz) was observed. Exposure to 100 mM lysozyme induced a more complex behavior (see Fig.…”

Well-defined biomimetic surfaces to characterize glycosaminoglycan-mediated interactions on the molecular, supramolecular and cellular levels

“…In particular, we expect SAv to be immobilized such that two of its four biotin-binding sites are facing the surface for immobilization while the other two binding sites are facing the solution to accommodate target molecules. In this regard, SAv performed better than neutravidin (which is perhaps more frequently used in molecular labelling applications), because neutravidin has an enhanced tendency to aggregate [35] and hence does not form well-defined monolayers. Biotin conjugation of the target molecule at a specific site affords immobilization at a well-defined and desired orientation on SAv monolayers.…”