A Graphene Oxide˙Streptavidin Complex for Biorecognition – Towards Affinity Purification

Abstract

In our postgenomic era, understanding of protein‐protein interactions by characterizing the structure of the corresponding protein complex is becoming increasingly important. An important problem is that many protein complexes are only stable for a few minutes. Dissociation will occur when using the typical, time‐consuming purification methods such as tandem affinity purification and multiple chromatographic separations. Therefore, there is an urgent need for a quick and efficient protein‐complex purification method for 3D structure characterization. The graphene oxide (GO)·streptavidin complex is prepared via a GO·biotin·streptavidin strategy and used for affinity purification. The complex shows a strong biotin recognition capability and an excellent loading capacity. Capturing biotinylated DNA, fluorophores and Au nanoparticles on the GO·streptavidin complexes demonstrates the usefulness of the GO·streptavidin complex as a docking matrix for affinity purification. GO shows a high transparency towards electron beams, making it specifically well suited for direct imaging by electron microscopy. The captured protein complex can be separated via a filtration process or even via on‐grid purification and used directly for single‐particle analysis via cryo‐electron microscopy. Therefore, the purification, sample preparation, and characterization are rolled into one single step.

A graphene functionalized electrochemical aptasensor for selective label-free detection of cancer cells

“…Fig. 2A 6 ] at different surfaces. A pair of welldefined oxidation and reduction peaks is observed at the PTCA/ CCG-Nafion modified electrode (red line) compared with the negligible currents at nafion-modified electrode (black line), which indicates that conductive graphene conjugation can facilitate electron transfer [42,43], as shown in Supporting Figs.…”

“…Electrochemical impedance spectroscopy (EIS) was performed using an EG&G Princeton Applied Research Model 273 potentiostat/galvanostat in 10 mM K 3 [Fe(CN) 6 ]/K 4 [Fe(CN) 6 ] (1:1) mixture with 1.0 M KCl as the supporting electrolyte. The impedance spectra ware recorded within the frequency range of 10 À2 e10 5 Hz.…”

Highly Sensitive Detection and Removal of Lead Ions in Water Using Cysteine-Functionalized Graphene Oxide/Polypyrrole Nanocomposite Film Electrode

“…, aromatic C=C (ν C=C at 1631 cm -1 ), epoxy C-O (ν C-O at 1242 cm -1 ) and alkoxy C-O (ν C-O ) at 1045 cm −1 [42][43]. Figure S2bshows the asymmetric stretching peak of -COO − at 1590 cm −1 and the symmetric stretching peak of -COO − at 1394 cm −1 in CySH.…”

Interactions of graphene and graphene oxide with proteins and peptides

“…The complex system shows a strong biotin recognition capability and an excellent loading capacity. It can capture biotinylated DNA, fluorophores, and Au nanoparticles demonstrating the usefulness as a docking matrix for the affinity purification of protein and other biomolecules [138] .…”