abstract
Partitioning of 11 globular proteins was examined in aqueous dextran-PEG-sodium/potassium phosphate buffer (0.01 M K/NaPB, pH 7.4) two-phase systems (ATPSs) containing 0.5 M sorbitol. The data obtained were analyzed together with those reported previously for the same proteins in osmolyte-free ATPS and ATPS containing 0.5 M sucrose, TMAO, or trehalose. It was found that all the partition coefficients for proteins determined in the presence of 0.5 M of different osmolytes and in the absence of osmolytes may be described in terms of the differences between solvent properties of the coexisting phases. Solute-specific coefficients characterizing different types of solute-solvent interactions were calculated for each protein. These solute-specific coefficients are linearly interrelated implying cooperativity of different types of protein-water interactions. The data obtained indicate the lack of any association of the aforementioned osmolytes at concentration of 0.5 M with proteins. Computational analysis of one of the solute-specific coefficient Ss-values characterizing dipole-dipole protein-water interactions shows that it is determined by the peculiarities of protein surface.
keywords
AQUEOUS 2-PHASE SYSTEMS; TRIMETHYLAMINE-N-OXIDE; PREFERENTIAL INTERACTIONS; SOLVENT INTERACTIONS; ELASMOBRANCH FISHES; UNFOLDED PROTEINS; AMINO-ACIDS; STABILIZATION; PREDICTION; MECHANISM
subject category
Chemistry
authors
Ferreira, LA; Fan, X; Madeira, PP; Kurgan, L; Uversky, VN; Zaslavsky, BY
our authors
Pedro António Palma Madeira
Junior Researcheracknowledgements
This work was supported in part by a grant from Russian Science Foundation RSCF No. 14-24-00131 (V. N. U.).