Nonfreezing Water Structuration in Heteroprotein Coacervates

作者：Du Xiaosong; Seeman Daniel^*; Dubin Paul L; Hoagland David A

来源：Langmuir, 2015, 31(31): 8661-8666.

DOI：10.1021/acs.langmuir.5b01647

Surface-bound water in protein solutions has been identified with a reduction in its freezing point. We studied the presence of such nonfreezing water (NFW) in various protein polyelectrolyte, micelle polyelectrolyte, and protein protein (heteroprotein) coacervates, along with appropriate concentrated solutions of macromolecules alone, finding up to 15% w/w NFVV for the heteroprotein coacervate of lactoferrin (LF) and beta-lactoglobulin (BLG). The level of NFW is always higher in coacervates than in the control (single macromolecule) systems, particularly for protein-containing coacervates: a coacervate of bovine serum albumin (BSA) and poly(dimethyldiallylammonium chloride) (PDADMAC) showed a ratio of NEW/protein twice that of BSA alone (0.6 vs 0.3), with a similarly high ratio for LF-BLG coacervate. These results are attributed to the maximization of water-protein contacts, structural features that reflect the mode of sample assembly, as they are not seen in a noncoacervated LF-BLG solution with identical concentrations of all species.

• 出版日期2015-8-11