Selective Chemical Labeling of Proteins with Small Fluorescent Molecules Based on Metal-Chelation Methodology

Site-specific chemical labeling utilizing small fluorescent molecules is apowerful and attractive technique for in vivo and in vitro analysis of cellular proteins,which can circumvent some problems in genetic encoding labeling by large fluorescentproteins. In particular, affinity labeling based on metal-chelation, advantageous due to thehigh selectivity/simplicity and the small tag-size, is promising, as well as enzymaticcovalent labeling, thereby a variety of novel methods have been studied in recent years.This review describes the advances in chemical labeling of proteins, especially highlightingthe metal-chelation methodology.