title: How does fluorescent labeling affect the binding kinetics of proteins with intact cells?
abstract: Fluorescent labeling is a mainstream technology for detecting molecular binding. Despite the importance, few studies have been devoted to quantitatively examine the effect of labeling on the molecular binding processes. Here we present a quantitative study on the binding kinetics of fluorescent-labeled and un-labeled molecules (lectin proteins) with glycoproteins on the membrane of cells using surface plasmon resonance imaging (SPRi) technique. The study shows that fluorescent labeling has a significant influence on the binding behaviors of proteins, especially the association processes, and the influence depends sensitively on the charge of fluorescent labels. It further shows that the labels also affect the local distribution of probe proteins, due to the inhomogeneous surface charge distribution of the cell membrane. Our work indicates that fluorescent labeling in general affects the binding behaviors, but proper design of the label will help to minimize its effect.
authors.affiliation: College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China; Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA.
authors.forename: Linliang
authors.initials: L
authors.lastname: Yin
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China. Electronic address: wei.wang@nju.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA.
authors.forename: Shaopeng
authors.initials: S
authors.lastname: Wang
authors.affiliation: Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA.
authors.forename: Fenni
authors.initials: F
authors.lastname: Zhang
authors.affiliation: College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China. Electronic address: stzhang@cqu.edu.cn.
authors.forename: Shengtao
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Center for Bioelectronics and Biosensors, Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA; State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China. Electronic address: njtao@asu.edu.
authors.forename: Nongjian
authors.initials: N
authors.lastname: Tao
mesh_terms: D015374:Biosensing Techniques; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D005456:Fluorescent Dyes; D006801:Humans; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000378:metabolism; D011485:Protein Binding; D020349:Surface Plasmon Resonance; D014909:Wheat Germ Agglutinins / Q000378:metabolism
chemical_list: D005456:Fluorescent Dyes; D008562:Membrane Glycoproteins; D014909:Wheat Germ Agglutinins
keywords: Binding kinetics; Fluorescent labeling; Lectin–glycoprotein interactions; Surface plasmon resonance imaging; Wheat germ agglutinin (WGA)