Ice formation and solvent nanoconfinement in protein crystals.

ABSTRACT: Ice formation within protein crystals is a major obstacle to the cryocrystallographic study of protein structure, and has limited studies of how the structural ensemble of a protein evolves with temperature in the biophysically interesting range from ∼260 K to the protein-solvent glass transition near 200 K. Using protein crystals with solvent cavities as large as ∼70 Å, time-resolved X-ray diffraction was used to study the response of protein and internal solvent during rapid cooling. Solvent nanoconfinement suppresses freezing temperatures and ice-nucleation rates so that ice-free, low-mosaicity diffraction data can be reliably collected down to 200 K without the use of cryoprotectants. Hexagonal ice (I_h) forms in external solvent, but internal crystal solvent forms stacking-d

SUBMITTER: Moreau DW 

PROVIDER: S-EPMC6503922 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature