LAUSR

Significance Accurately capturing the intricate interaction networks that control protein allostery is a central goal in protein science. We present a means to determine these networks by high-resolution NMR difference and coupling measurements, illustrated for pH-dependent myristoyl switching in hisactophilin. Integrated temperature and pH dependence of protein amide NMR synergistic with molecular dynamics (MD) simulations resolves nuances of a proteinwide interaction network, with proton binding by histidines in balance with extensive core and surface hydrophobic interactions. Analysis of mutant proteins demonstrates how this web of switching interactions can be broken, restored, and tuned. Thus, high-sensitivity NMR may be used to define the intricacies of interaction networks in a wide variety of protein and peptide systems.