Control of Protein Conformation and Orientation on Graphene

Abstract

Graphene-based biosensors have attracted considerable attention due to their advantages of label-free detection and high sensitivity. Many such biosensors utilize noncovalent van der Waals force to attach proteins onto graphene surface while preserving graphene's high conductivity. Maintaining the protein structure without denaturation/substantial conformational change and controlling proper protein orientation on the graphene surface are critical for biosensing applications of these biosensors fabricated with proteins on graphene. Based on the knowledge we obtained from our previous experimental study and computer modeling of amino acid residual level interactions between graphene and peptides, here we systemically redesigned an important protein for better conformational stability and desirable orientation on graphene. In this paper, immunoglobulin G (IgG) antibody-binding domain of protein G (protein GB1) was studied to demonstrate how we can preserve the protein native structure and control the protein orientation on graphene surface by redesigning protein mutants. Various experimental tools including sum frequency generation vibrational spectroscopy, attenuated total refection-Fourier transform infrared spectroscopy, fluorescence spectroscopy, and circular dichroism spectroscopy were used to study the protein GB1 structure on graphene, supplemented by molecular dynamics simulations. By carefully designing the protein GB1 mutant, we can avoid strong unfavorable interactions between protein and graphene to preserve protein conformation and to enable the protein to adopt a preferred orientation. The methodology developed in this study is general and can be applied to study different proteins on graphene and beyond. With the knowledge obtained from this research, one could apply this method to optimize protein function on surfaces (e.g., to enhance biosensor sensitivity).

Metal–Organic Frameworks for Enzyme Immobilization: Beyond Host Matrix Materials

“…The technique of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) is combined to determine the complicated protein interfacial structure as well as the orientation with micrometers of penetration depth. In a recent report from the same group, 55 the immunoglobulin G (IgG) antibody-binding domain of protein G (protein GB1) was selected as the model protein, and it demonstrated how this technique actualized to control the protein orientation on the graphene by redesigning the protein mutants but retained the native structure. The interaction of protein–graphene was investigated by SFG, CD, and fluorescence spectroscopy and was supplemented by MD simulations.…”

“…Color means matching probability. 55 (b) Experimental sample space of SBA-15 (6.4) (top, left), and SANS patterns and model fit of SBA-15 (8.1 nm) (bottom, left). SANS of myoglobin and lysozyme loaded SBA-15 (6.4 and 8.1 nm) (right).…”

Conductive Biomaterials as Bioactive Wound Dressing for Wound Healing and Skin Tissue Engineering

“…Graphene possessing excellent conductivity at room temperature than any other carbon materials, a high optical absorptivity, high thermal conductivity, and high mechanical strength has great value in many fields [ 135 ]. However, graphene tends to aggregate, and the poor dispersion extremely restricts its application, especially as biomaterials.…”

In silico design of peptides with binding to the receptor binding domain (RBD) of the SARS-CoV-2 and their utility in bio-sensor development for SARS-CoV-2 detection

“…Similar ndings related to the deformation of proteins in presence of graphene has been reported earlier. 30,31 The hydrophobic surface of the graphene selectively interacts with the Table 2 The amino acid sequence of peptide 6 and 7. The amino acids glutamic acid (E) and lysine (K) are highlighted in red where linker was attached.…”