Using capillary electrophoresis mobility shift assay to study the interaction of CdTe quantum dots with bovine serum albumin

In this work, the capillary electrophoresis mobility shift assay （CEMSA） was first adopted to study the interaction of protein with quantum dots （QDs）. In this study, bovine serum albumin （BSA） and CdTe QDs were used as model samples. We observed that BSA was facilely adsorbed to CdTe QDs surface, and the QD-BSA complex was formed by a 1：1 stoichiometric ratio. A value of 2.17 4-0.27 × 10^6 mol^-1 L^-1 （at 25 ℃） for the association constant was obtained by CEMSA.

Resolving the geometric structure of trastuzumab by mobility capillary electrophoresis and native mass spectrometry

Available online Immunoglobulins G(IgGs)are Y-shaped globular proteins,however,their high flexibility and heterogeneity pose great challenges to their structure and conformation determinations.Geometric structure of IgG closely correlates to its biofunctions,such as the antibody escape of human immunodeficiency virus(HIV)could attribute to the distance mismatch between the ends of two Fab arms(antigen-binding sites)and envelope glycoprotein spikes on virion surface.Herein,we report the first use of mobility capillary electrophoresis(MCE)and native mass spectrometry(nMS)to resolve the internal geometric structure and conformation of an IgG(trastuzumab)in solution phase.After proteolysis,the ellipsoid dimensions of IgG and its subunits were measured by MCE-nMS experiments.IgG was then reconstructed,in which the sizes and relative positions of these three subunits in three-dimensional space were characterized.It was found that the two Fab arms have an angle of~102.1°and a distance of~11.0 nm between the two antigen-binding sites under native condition,and the Fc arm was tilted~16.0°towards one of the Fab arms.Fc was not on the plane of Fab-Fab,but has an angle of no larger than 103.1°.Under acidic environment(pH 3.0),each subunit of the IgG would unfold into larger dimensions,and the angles between these subunits also change.With great potential for tumor imaging and therapy,the structure of F(ab')_(2)fragments was also measured and validated by molecular dynamic simulation.It was found that the electrostatic force among these three subunits and steric hindrance stemming from Fc help maintaining the angle between two Fab arms.

A Rapid and Cost-Effective Method for Genotyping Genome-Edited Animals：A Heteroduplex Mobility Assay Using Microfluidic Capillary Electrophoresis

The recent emergence and application of engineered endonucleases have led to the development of genome editing tools capable of rapidly implementing various targeted genome editions in a wide range of species.Moreover,these novel tools have become easier to use and have resulted in a great increase of applications.Whilst gene knockout（KO） or knockin（KI） animal models are relatively easy to achieve,there is a bottleneck in the detection and analysis of these mutations.Although several methods exist to detect these targeted mutations,we developed a heteroduplex mobility assay on an automated microfluidic capillary electrophoresis system named HMA-CE in order to accelerate the genotyping process.The HMA-CE method uses a simple PCR amplification of genomic DNA（gDNA） followed by an automated capillary electrophoresis step which reveals a heteroduplexes（HD） signature for each mutation.This allows efficient discrimination of wild-type and genome-edited animals down to the single base pair level.