Investigation of the weak binding of a tetrahistidine‐tagged peptide to quantum dots by using capillary electrophoresis with fluorescence detection

Abstract

Capillary electrophoresis with fluorescence detection was utilized to probe the self-assembly between cyanine group dye labeled tetrahistidine containing peptide and CdSe/ZnS quantum dots, inside the capillary. Quantum dots and cyanine group dye labeled tetrahistidine containing peptide were injected into the capillary one after the other and allowed to self-assemble. Their self-assembly resulted into a measurable Förster resonance energy transfer signal between quantum dots and cyanine group dye labeled tetrahistidine containing peptide. The Förster resonance energy transfer signal increased upon increasing the cyanine group dye labeled tetrahistidine containing peptide/quantum dot molar ratio and reached a plateau at the 32/1 molar ratio. Additionally, the Förster resonance energy transfer signal was also affected by the increment of the interval time of injection and the sampling time. Online ligand exchange experiments were used to assess, the potential of a monovalent ligand of imidazole and a hexavalent ligand peptide, to displace surface bound cyanine group dye labeled peptide ligands from the quantum dots surface. Under optimal conditions, a linear relationship between the integrated peak areas and hexavalent ligand peptide was obtained at a hexavalent ligand concentration range of 0-0.5 mM. Therefore, the present assay has the potential to be applied in the online ligands detection.

Recent developments in capillary and microchip electroseparations of peptides (2015–mid 2017)

“…Analyses were performed in 75 μm id capillary with 60/35 cm total/effective length, in 25 mM sodium tetraborate BGE, pH 9.3, at separation voltage 18 kV. The same instrumentation, methodology, and BGE were employed for investigation of a large series of interactions (self‐assembly) between oligo‐ and polypeptides of different lengths and charges (mostly tagged with hexahistidine anchor) and CdSe/ZnS quantum dots or between peptides conjugated to these quantum dots and other peptides or proteins, e.g. characterization of self assembly of glutathione stabilized CdSe/ZnS quantum dots and cyanine5‐labeled peptide (cyanine5‐Glu(Ala) 5 (His) 6 ) , detection of assembly and imidazole‐induced disassembly of multivalent HA tag peptide with hexahistidine at C‐terminus and anti‐HA monoclonal antibody , and study of multivalent interactions between conjugate of quantum dots with c‐Myc peptide tag and the anti‐c‐Myc monoclonal antibody .…”

CE Separation and ICP-MS Detection of Gold Nanoparticles and Their Protein Conjugates

“…On the other hand, techniques such as ESI–MS [ 14 – 16 ] and transmission electron microscopy [ 17 ] require that the excess of protein is removed prior to or during analysis. Application of the separation-based techniques, such as liquid/nanoliquid chromatography, capillary electrophoresis (CE) and gel electrophoresis, in investigations of the protein-bound nanoparticles has received a great deal of recent research trials [ 18 – 32 ]. Among these methods, CE has been most widely used to explore nano–bio interactions, as follows from a recent literature examination by Aleksenko et al [ 33 ].…”

Characterization of interactions of metal‐containing nanoparticles with biomolecules by CE: An update (2012–2016)

“…down to 2 × 10 −10 M for γ‐Fe 2 O 3 ‐silica core‐shell nanoparticles functionalized with PEG ) or after surface modification by the attachment of a fluorescence probe . Additionally, fluorescence measurements based on use of inverted fluorescence microscope have been applied to monitor the self‐assembling of QDs with various biomolecules inside the capillary and also with QDs added to BGE (as a probe), to determine various biomolecules [; see also a commentary on this topic by Vaculovicova et al. ) or to characterize biomolecule‒biomolecule interactions .…”