Nano-rheology measurements reveal that the hydration layer of enzymes partially controls conformational dynamics

作者：Alavi Zahra; Ariyaratne Amila; Zocchi Giovanni^*

来源：Applied Physics Letters, 2015, 106(20): 203702.

DOI：10.1063/1.4921414

For a typical (20 kD, 4 nm size) monomeric enzyme, more than 50% of the residues are at the surface. The mechanics of these soft, heterogeneous nanoparticles was recently shown to be viscoelastic. Here, we explore the contribution of the enzyme's surface to the mechanics of the molecule. Nano-rheology provides sub-angstrom resolution measurements of the reversible deformation of the enzyme subject to an oscillatory mechanical stress. We perturb the surface of the enzyme by adding small amounts of DMSO (dimethyl sulfoxide), believed to affect ordering of the enzyme-water interface. We observe a dramatic though reversible change in the mechanics of the enzyme, which becomes more viscous. On the other hand, the catalytic speed is unaffected, while at higher DMSO concentrations (>1%) it even increases.

• 出版日期2015-5-18