Design and evaluation of a cyclobutane diazirine alkyne tag for photoaffinity labeling in cells

ABSTRACT: Alkyl diazirines are frequently used in photoaffinity labeling to trap and identify small molecule–protein interactions. How-ever, the alkyl diazirine can preferentially label acidic amino acids and acidic protein surfaces in a pH-dependent manner, presumably via a long-lived alkyl diazo intermediate. To alter this reactivity preference, we developed PALBOX, a novel cyclobutane diazirine photoaffinity tag with reduced pH-dependent reactivity. We show that PALBOX is readily derivatized and attached to small molecules to profile their binding interactions in cells. Systematic experiments with biological sub-strates show that the cyclobutane diazirine scaffold does not exhibit reactivity characteristic of unconstrained alkyl diazo in-termediates. Using a set of small molecule fragments and ligands, we show that photoaffinity probes equipped with PALBOX can label known protein targets in cells with higher specificity. Finally, we demonstrate that ligands equipped with PALBOX can accurately map small molecule–protein binding sites. Thus, PALBOX is a versatile diazirine-based pho-toaffinity tag for use in the development of chemical probes for photoaffinity labeling experiments, including the study of small molecule–protein interactions.

INSTRUMENT(S):

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture

SUBMITTER: Christina Woo  

LAB HEAD: Christina M. Woo

PROVIDER: PXD035954 | Pride | 2024-01-04

REPOSITORIES: Pride