Controlling Multivalent Binding through Surface Chemistry: Model Study on Streptavidin

Abstract

Although multivalent binding to surfaces is an important tool in nanotechnology, quantitative information about the residual valency and orientation of surface-bound molecules is missing. To address these questions, we study streptavidin (SAv) binding to commonly used biotinylated surfaces such as supported lipid bilayers (SLBs) and self-assembled monolayers (SAMs). Stability and kinetics of SAv binding are characterized by quartz crystal microbalance with dissipation monitoring, while the residual valency of immobilized SAv is quantified using spectroscopic ellipsometry by monitoring binding of biotinylated probes. Purpose-designed SAv constructs having controlled valencies (mono-, di-, trivalent in terms of biotin-binding sites) are studied to rationalize the results obtained on regular (tetravalent) SAv. We find that divalent interaction of SAv with biotinylated surfaces is a strict requirement for stable immobilization, while monovalent attachment is reversible and, in the case of SLBs, leads to the extraction of biotinylated lipids from the bilayer. The surface density and lateral mobility of biotin, and the SAv surface coverage are all found to influence the average orientation and residual valency of SAv on a biotinylated surface. We demonstrate how the residual valency can be adjusted to one or two biotin binding sites per immobilized SAv by choosing appropriate surface chemistry. The obtained results provide means for the rational design of surface-confined supramolecular architectures involving specific biointeractions at tunable valency. This knowledge can be used for the development of well-defined bioactive coatings, biosensors and biomimetic model systems.

Formation of Alkanethiol Supported Hybrid Membranes Revisited

“…The modified surfaces displayed a WCA larger than 100° (102.2 ± 0.4° for octanethiol and 107.4 ± 1.1° for hexadecanethiol), while the original oxidized gold surface exhibited a smaller WCA of 78.9 ± 2.9°. The results are consistent with literature data …”

Elasticity‐Dependent Fast Underwater Adhesion Demonstrated by Macroscopic Supramolecular Assembly

“…Thea bove modulus-dependent MSA phenomenon is interpreted by the theory of multivalency, [23][24][25][26][27][28][29] which describes the enhancement of the binding forces between large interfaces common in biological systems, [24][25][26] such as interactive virus/cell, cell/cell, proteins,o ra rtificial intervesicular interaction systems. [27][28][29] With as imilar surface chemistry,t he key to realizing multivalencyi st he substrate deformability,which determines the molecular motility of the interactive moieties.…”

Diselenolane‐Mediated Cellular Uptake: Efficient Cytosolic Delivery of Probes, Peptides, Proteins, Artificial Metalloenzymes and Protein‐Coated Quantum Dots

“…All complex stoichiometries given in the following refer to mixing ratios, real existing product mixtures are naturally more complex. [5,6,19] The complexes 10 were efficiently taken up into HeLa Kyoto cells( Figure 2C), while control complexes 12 without DiSeL tag 8 were inactive( Figure 2B). Analogous complexes prepared with biotinylated AspA and ETP tags gave clearly weaker uptake efficiency (Figures S1, S2).…”

“…[17] The biotinylated DiSeL tag 8 was synthesized [18] for general non-covalent connection to the substrate through the tetravalent streptavidin (Sav) 9,a% 60 kDa protein ( Figure 2). [5,6,19] Complexes 10 were prepared by mixingS av 9 with biotinylated fluorophores 11 and biotinylated DiSeL tag 8 in a3:1 ratio. All complex stoichiometries given in the following refer to mixing ratios, real existing product mixtures are naturally more complex.…”