Journal of the American Chemical Society 2020
DOI: 10.1021/jacs.0c01325
Reactive cellular metabolites can modify macromolecules and form adducts known as non-enzymatic covalent modifications (NECMs). Dissecting the mechanisms, regulation and consequences of NECMs, such as glycation, has been challenging due to the complex and often ambiguous nature of the adducts formed. Directly tracking the formation of modifications on key targets to uncover their underlying physiological importance requires specific chemical tools. Here we present the novel chemoenzymatic syntheses of an active azido-modified ribose analog, 5-azidoribose (5-AR), as well as an inactive control derivative, 1-azidoribose (1-AR) and their application towards understanding protein ribose-glycation in vitro and in cellulo. With these new probes we found that, similar to MGO-glycation, ribose glycation specifically accumulates on histones. In addition to fluorescent labeling, we demonstrate the utility of the probe in enriching modified targets, which were identified by label-free quantitative proteomics and high-resolution MS/MS workflows. Finally, we establish that the known oncoprotein and hexose deglycase, fructosamine 3-kinase (FN3K), recognizes and facilitates the removal of 5-AR glycation adducts in live cells, supporting the dynamic regulation of ribose glycation as well as validating the probe as a new chemical tool to monitor FN3K activity. Altogether, we demonstrate this probe’s utilities to uncover ribose-glycation and deglycation events as well as tracking FN3K activity towards establishing its potential as a new cancer vulnerability.
