Tryptoline stereoprobe elaboration identifies inhibitors of the GRPEL1-HSPA9 complex.

Tryptoline acrylamide stereoprobes can disrupt the GRPEL1-HSPA9 complex by targeting nonorthosteric sites, impairing mitochondrial protein import and mitophagy.

• Why it matters: Understanding how stereoprobes interact with proteins at nonorthosteric sites is crucial for developing covalent ligands that modulate protein functions beyond traditional active sites, which can lead to new therapeutic strategies.
• What they did: The study used activity-based protein profiling and structural modifications of tryptoline acrylamides to analyze their interactions with human proteins, revealing that most liganding occurred at nonorthosteric sites and evaded machine learning predictions.
• The result: Disruption of the GRPEL1-HSPA9 interaction by stereoprobes at C124 impairs mitochondrial functions, demonstrating that tryptoline acrylamides serve as versatile covalent tools targeting nonorthosteric sites on proteins.