A fine balance of hydrophobic-electrostatic communication pathways in a pH-switching protein.

Allostery is the phenomenon of coupling between distal binding sites in a protein. Such coupling is at the crux of protein function and regulation in a myriad of scenarios, yet determining the molecular mechanisms of coupling networks in proteins remains a major challenge. Here, we report mechanisms governing pH-dependent myristoyl switching in monomeric hisactophilin, whereby the myristoyl moves between a sequestered state, i.

Temperature dependence of NMR chemical shifts: Tracking and statistical analysis.

Isotropic chemical shifts measured by solution nuclear magnetic resonance (NMR) spectroscopy offer extensive insights into protein structure and dynamics. Temperature dependences add a valuable dimension; notably, the temperature dependences of amide proton chemical shifts are valuable probes of hydrogen bonding, temperature-dependent loss of structure, and exchange between distinct protein conformations. Accordingly, their uses include structural analysis of both folded and disordered proteins, and determination of the effects of mutations, binding, or solution conditions on protein energetics.

Dissecting the molecular determinants of ligand-binding-induced macromolecular switching using thermodynamic cycles.

The energetic networks that govern regulated switching processes in macromolecules are poorly understood at a molecular level. We illustrate a general methodology that uses thermodynamic cycles to measure the coupling energetics between specific groups in a macromolecule and ligand-binding-induced macromolecular switching. The approach is applied to new and published thermodynamic stability and/or binding data not previously analyzed in this way, for a wide range of switching systems, including H+ or Ca²+-binding-induced myristoyl switching, ion or peptide-binding-induced conformational switching in various proteins and small molecule binding to a ribo-switch.