Identification of a mechanical rheostat in the hydrophobic core of protein L.

摘要: The ability of proteins and their complexes to withstand or respond mechanical stimuli is vital for cells maintain structural organisation, relay external signals facilitate unfolding remodelling. Force spectroscopy using the atomic force microscope allows behaviour single protein molecules under an applied extension be investigated strength quantified. L, a simple model protein, displays moderate thought unfold by shearing two sub-domains. Here, we investigate importance side-chain packing L measuring series variants containing conservative hydrophobic volume deletion mutants. Of five thermodynamically destabilised characterised, only one residue (I60V) close interface between sub-domains was found differ in properties wild type (ΔFI60V–WT = − 36 pN at 447 nm s− 1, ΔxuI60V–WT = 0.2 nm). Φ-value analysis data revealed highly native transition state. To test whether number contacts across does affect measured further variants. L10F, which increases core but not enhance interfacial contacts, increased 13 ± 11 pN s− 1. By contrast, I60F, both cross-interface 72 ± 13 pN These suggest method nature can evolve varied response from limited topologies demonstrate generic facile rationally modified.