Recently, it was shown that the spectral graph theory is exceptionally useful for understanding not only morphological structural differences in ion aggregates but also similarities between an ion network and a water H-bonding network in highly concentrated salt solutions. Here, we present spectral graph analysis results on osmolyte aggregates and water H-bonding network structures in aqueous r...

Protein solvation is the key determinant for isothermal, concentration-dependent effects on protein equilibria, such as folding. The required solvation information can be extracted from experimental thermodynamic data using Kirkwood-Buff theory. Here we derive and discuss general properties of proteins and osmolytes that are pertinent to their biochemical behavior. We find that hydration depend...

We study the solvation of amino acids in pure-osmolyte and mixed-osmolyte urea and trimethylamine N-oxide (TMAO) solutions using molecular dynamics simulations. Analysis of Kirkwood-Buff integrals between the solution components provides evidence that in the mixed osmolytic solution, both urea and TMAO are mutually excluded from the amino acid surface, accompanied by an increase in osmolyte-osm...

The uptake and accumulation of the potent osmolytes glycine betaine and carnitine enable the food-borne pathogen Listeria monocytogenes to proliferate in environments of elevated osmotic stress, often rendering salt-based food preservation inadequate. To date, three osmolyte transport systems are known to operate in L. monocytogenes: glycine betaine porter I (BetL), glycine betaine porter II (G...

Cells subjected to sustained high osmolarity almost universally respond by accumulating compatible organic osmolytes that, in contrast to inorganic ions, are not deleterious even at high intracellular concentrations. Their accumulation from the external environment by known organic osmolyte transporters, such as the four identified in mammals, occurs only slowly in response to sustained high os...

Osmolyte transport is a pivotal part of bacterial life, particularly in high salt environments. Several low and high affinity osmolyte transport systems have been identified in various bacterial species. A lot of research has centered on characterizing the osmolyte transport systems of Gram-negative bacteria, but less has been done to characterize the same transport systems in Gram-positive bac...

We study the buckling of elastic spherical shells under osmotic pressure with the osmolyte concentration of the exterior solution as a control parameter. We compare our results for the bifurcation behavior with results for buckling under mechanical pressure control, that is, with an empty capsule interior. We find striking differences for the buckling states between osmotic and mechanical buckl...

Longstanding mechanistic questions about the role of protecting osmolyte trimethylamine N oxide (TMAO) which favors protein folding and the denaturing osmolyte urea are addressed by studying their effects on the folding of uncharged polymer chains. Using atomistic molecular dynamics simulations, we show that 1-M TMAO and 7-M urea solutions act dramatically differently on these model polymer cha...

Longstanding mechanistic questions about the role of protecting osmolyte trimethylamine N-oxide (TMAO) that favors protein folding and the denaturing osmolyte urea are addressed by studying their effects on the folding of uncharged polymer chains. Using atomistic molecular dynamics simulations, we show that 1 M TMAO and 7 M urea solutions act dramatically differently on these model polymer chai...

We seek to understand the link between protein thermodynamics and protein structure in molecular detail. A classical approach to this problem involves assessing changes in protein stability resulting from added cosolvents. Under any given conditions, protein molecules in aqueous buffer are in equilibrium between unfolded and folded states, U(nfolded) <==> N(ative). Addition of organic osmolytes...