Talin-drug interaction reveals a key molecular determinant for biphasic mechanical effect: studied under single-molecule resolution

Abstract

Talin as an adhesion protein, exhibits a strong force-dependent structure-function dynamics. Being a mechanosensitive focal adhesion (FA) protein, talin might interact to several FA targeting drugs; however, the molecular mechanism of talin-drug interactions remains elusive. Here we combined magnetic tweezers and molecular dynamics (MD) simulation to explore mechanical stability of talin with three drugs based on their talin specificity. Interestingly, our study revealed that talin displays a bimodal force distribution with a low and high unfolding force population. We observed that talin nonspecific drugs (tamoxifen and letrozole) display biphasic effect: increase talin mechanical stability upto optimum concentration, followed by a decrease in stability with further concentration increase. By contrast, talin-specific cyanidin 3-O-glucoside promotes a steady increase to talin mechanical stability with its concentration. We reconciled our observation from the simulation study: tamoxifen enters into talin hydrophobic core, eventually destabilizing the protein; whereas cyanidin 3-O-glucoside stabilizes the protein core by maintaining the inter-helix distance. Finally, we observed a strong correlation among hydrophobicity and cavity analysis, illustrating a detailed mechanistic analysis of drug effect on the mechanosensitive protein. Overall this study presents a novel perspective for drug designing against mechanosensitive proteins and studying off-target effects of already known drugs.