Control of Solvent Dynamics around the B12-Dependent Ethanolamine Ammonia-Lyase Enzyme in Frozen Aqueous Solution by Using Dimethyl Sulfoxide Modulation of Mesodomain Volume.

ABSTRACT: The temperature-dependent structure and dynamics of two concentric solvent phases, the protein-associated domain (PAD) and the mesodomain, that surround the ethanolamine ammonia-lyase (EAL) protein from Salmonella typhimurium in frozen polycrystalline aqueous solution are addressed by using electron paramagnetic resonance spectroscopy of the paramagnetic nitroxide spin probe, TEMPOL, over the temperature ( T) range 190-265 K. Dimethyl sulfoxide (DMSO), added at 0.5, 2.0, and 4.0% v/v and present at the maximum freeze concentration at T ≤ 245 K, varies the volume of the interstitial aqueous DMSO mesodomain ( Vmeso) relative to a fixed PAD volume ( VPAD). The increase in Vmeso/ VPAD from 0.8 to 6.0 is quantified by the partitioning of TEMPOL between the two phases. As Vmeso/ VPAD is increase

SUBMITTER: Nforneh B 

PROVIDER: S-EPMC7387330 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature