Development of α-helical calpain probes by mimicking a natural protein-protein interaction

Autor: Jo, Hyunil, Meinhardt, Nataline, Wu, Yibing, Kulkarni, Swapnil, Hu, Xiaozhen, Low, Kristin E, Davies, Peter L, DeGrado, William F, Greenbaum, Doron C
Rok vydání: 2012
Předmět:
Zdroj: Journal of the American Chemical Society, vol 134, iss 42
Popis: We have designed a highly specific inhibitor of calpain by mimicking a natural protein-protein interaction between calpain and its endogenous inhibitor calpastatin. To enable this goal we established a new method of stabilizing an α-helix in a small peptide by screening 24 commercially available cross-linkers for successful cysteine alkylation in a model peptide sequence. The effects of cross-linking on the α-helicity of selected peptides were examined by CD and NMR spectroscopy, and revealed structurally rigid cross-linkers to be the best at stabilizing α-helices. We applied this strategy to the design of inhibitors of calpain that are based on calpastatin, an intrinsically unstable polypeptide that becomes structured upon binding to the enzyme. A two-turn α-helix that binds proximal to the active site cleft was stabilized, resulting in a potent and selective inhibitor for calpain. We further expanded the utility of this inhibitor by developing irreversible calpain family activity-based probes (ABPs), which retained the specificity of the stabilized helical inhibitor. We believe the inhibitor and ABPs will be useful for future investigation of calpains, while the cross-linking technique will enable exploration of other protein-protein interactions.
Databáze: OpenAIRE