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Sci Rep

Title:		Effects of disulfide bridges and backbone connectivity on water sorption by protein matrices
Author(s):		Kim SB; Singh RS; Paul PKC; Debenedetti PG;
Address:		"Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, 08544, United States. Unilever R&D, Port Sunlight Laboratory, Wirral, CH63 3JW, United Kingdom. Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, 08544, United States. pdebene@princeton.edu"
Journal Title:		Sci Rep
Year:		2017
Volume:		20170811
Issue:		1
Page Number:		7957 -
DOI:		10.1038/s41598-017-08561-2
ISSN/ISBN:		2045-2322 (Electronic) 2045-2322 (Linking)
Abstract:		"Understanding the water sorption behavior of protein powders is important in applications such as the preservation of protein-based pharmaceuticals. Most globular proteins exhibit a characteristic sigmoidal water adsorption isotherm at ambient conditions. However, it is not well understood how water sorption behavior is influenced by intrinsic factors that are related to structural properties of proteins. We investigate computationally how structural constraints on proteins influence the water sorption isotherms of amorphous protein powders. Specifically, we study the effects of non-local disulfide linkages and backbone connectivity using pheromone ER-23 and lysozyme as model proteins. We find that non-local disulfide linkages can significantly restrict structural changes during hydration and dehydration, and this in turn greatly reduces the extent of hysteresis between the adsorption and desorption branches. Upon removing the backbone connectivity by breaking all peptide bonds in lysozyme, we find that the hysteresis shifts towards the lower humidity regime, and the water uptake capacity is significantly enhanced. We attribute these changes to the higher aggregation propensity of the constraint-free amino acids in dehydrated condition, and the formation of a spanning water network at high hydration levels"
Keywords:		"Disulfides/*chemistry Models, Molecular Molecular Dynamics Simulation Muramidase/chemistry Pheromones/*chemistry Powders/chemistry Propensity Score Thermodynamics Water/*chemistry;"
Notes:		"MedlineKim, Sang Beom Singh, Rakesh S Paul, Prem K C Debenedetti, Pablo G eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. England 2017/08/13 Sci Rep. 2017 Aug 11; 7(1):7957. doi: 10.1038/s41598-017-08561-2"