A Critical Evaluation of Detergent Exchange Methodologies for Membrane Protein Native Mass Spectrometry.

Membrane proteins (MPs) play many critical roles in cellular physiology and constitute the majority of current pharmaceutical targets. However, MPs are comparatively understudied relative to soluble proteins due to the challenges associated with their solubilization in membrane mimetics. Native mass spectrometry (nMS) has emerged as a useful technique to probe the structures of MPs.

Verteporfin is a substrate-selective γ-secretase inhibitor that binds the amyloid precursor protein transmembrane domain.

This work reports substrate-selective inhibition of a protease with broad substrate specificity based on direct binding of a small-molecule inhibitor to the substrate. The target for these studies was γ-secretase protease, which cleaves dozens of different single-span membrane protein substrates, including both the C99 domain of the human amyloid precursor protein and the Notch receptor. Substrate-specific inhibition of C99 cleavage is desirable to reduce production of the amyloid-β polypeptide without inhibiting Notch cleavage, a major source of toxicity associated with broad specificity γ-secretase inhibitors.