Structure and function of nanoparticle–protein conjugates

Abstract

Conjugation of proteins to nanoparticles has numerous applications in sensing, imaging, delivery, catalysis, therapy and control of protein structure and activity. Therefore, characterizing the nanoparticle-protein interface is of great importance. A variety of covalent and non-covalent linking chemistries have been reported for nanoparticle attachment. Site-specific labeling is desirable in order to control the protein orientation on the nanoparticle, which is crucial in many applications such as fluorescence resonance energy transfer. We evaluate methods for successful site-specific attachment. Typically, a specific protein residue is linked directly to the nanoparticle core or to the ligand. As conjugation often affects the protein structure and function, techniques to probe structure and activity are assessed. We also examine how molecular dynamics simulations of conjugates would complete those experimental techniques in order to provide atomistic details on the effect of nanoparticle attachment. Characterization studies of nanoparticle-protein complexes show that the structure and function are influenced by the chemistry of the nanoparticle ligand, the nanoparticle size, the nanoparticle material, the stoichiometry of the conjugates, the labeling site on the protein and the nature of the linkage (covalent versus non-covalent).

Quantitative Nanoproteomics for Protein Complexes (QNanoPX) Related to Estrogen Transcriptional Action

“…A 25-l sample fraction was injected, concentrated by a C 18 nanoprecolumn cartridge (300-m inner diameter ϫ 1 mm, 5-m C 18 , P/N160458, LC Packings), and then separated by a C 18 column (75-m inner diameter, 280-m outer diameter ϫ 15 cm, 3-m C 18 , LC Packings). Mobile phase A consisted of 0.1% formic acid in 5% acetonitrile solution, and mobile phase B consisted of 0.1% formic acid in 80% acetonitrile solution; a linear gradient from 5 to 90% B over a 90-min period at a flow rate of 250 nl/min was applied.…”

“…This ability opens up new avenues of research because the traditional TCA precipitation method is ineffective under those conditions (16). Modified AuNPs have been successfully used by other groups for the detection of DNAs (17) and proteins (18) as well as for the fabrication of biosensors. In addition, the surface-only binding of AuNPs imposes no limitation on the size of protein complexes and eliminates the requirement for pore penetration, both of which are useful for IP experiments.…”

Topology of Surface Ligands on Liposomes: Characterization Based on the Terms, Incorporation Ratio, Surface Anchor Density, and Reaction Yield

“…[21][22][23] Because the modified micelles have the ability to bind to targeting receptors, it is important to determine the purity of the liposomes, and to evaluate the density of surface ligands, [24][25][26][27][28] which serve as an index of the quality of the liposomes. [29][30][31][32] Surface reaction modification can efficiently modify the liposomal surface without micelle contamination, and ensures that the ligands are orientated facing outward from the membrane. Pan et al applied both the post-insertion method and the surface reaction modification method to introduce cetuximab, a monoclonal antibody (mAb), against the human epidermal growth factor receptor (EGFR) on F98 EGFR glioma cells as ligands on the liposomal surface for active targeting delivery.…”

Synthesis of Gold Nanoparticles Coated with Aspartic Acid and Their Conjugation with FVIII Protein and FVIII Antibody

“…As can be seen in the Fig. 6a: FVIII, b: IgG the bonds in conjugated sample are displaced from that of standard sample [23][24][25][26]. Increasing the protein concentration decreases the shift extent of conjugated protein bonds to the nanoparticles one.…”