Bioorthogonal Click Chemistry: Covalent Labeling in Living Systems

Abstract

The term "click chemistry" defines a powerful set of chemical reactions that are rapid, selective, and high-yielding. These reactions, some of which are less than 10 years old, have been applied in diverse areas, including drug discovery, materials science, and chemical biology. In chemical biology, click chemistry has been used in the selective labeling of biomolecules within living systems, allowing proteins, glycans, and other important biomolecules to be monitored in a physiologically relevant environment rather than in an in vitro setting. This demanding application requires not only the aforementioned characteristics of click chemistry but, additionally, that the reactions are bioorthogonal -that is, non-interacting with biological functionality while proceeding under physiological conditions -and that the reagents are non-toxic. Of the many extant click reactions, only a select few possess this unique combination of attributes, notably the Staudinger ligation of azides and triarylphosphines and [3 þ 2] dipolar cycloadditions of azides with strained alkynes. This minireview describes the characteristics of bioorthogonal click reactions as well as recent applications toward labeling biomolecules in cells and living organisms.

Increasing the Efficacy of Bioorthogonal Click Reactions for Bioconjugation: A Comparative Study

“…[1] By hijacking a cells biosynthetic machinery, a metabolic precursor functionalized with a bioorthogonal chemical tag is incorporated into target biomolecules, including glycans, [2] lipids, [3] proteins, [4] and nucleic acids. [5] Subsequently, a tailor-designed click reaction is employed to conjugate a complementary biophysical probe, which enables visualization [2] or enrichment of the target biomolecules for molecular identification.…”

One-pot, additive-free preparation of functionalized polyurethanes via amine–thiol–ene conjugation

“…9 The toolbox of research labs is currently loaded with a variety of established 'click' 24 reactions, offering ample possibilities for macromolecular design and synthesis. Moreover, the 25 development and valorization of novel polymer materials with a broad range of applications 26 (medicines, [10][11][12][13] electronics, [14][15][16] bioconjugation, 17-21 labeling, [22][23][24][25][26] etc.) significantly promoted 27 interdisciplinary research.…”

Discovery of Escherichia coli methionyl-tRNA synthetase mutants for efficient labeling of proteins with azidonorleucine in vivo

“…The value and versatility of noncanonical amino acids has been increased significantly by their recent use in conjugation (9,10), detection (11,12), and selective isolation (13) of proteins. Among the reactive groups introduced into biological molecules, azides are especially useful (14). Azides can be ligated under physiological conditions to phosphines through the Staudinger ligation or to terminal alkynes through Cu(I)-catalyzed [3 ϩ 2] azide-alkyne cycloaddition, both in bioorthogonal fashion.…”