Combined influence of ectoine and salt: spectroscopic and numerical evidence for compensating effects on aqueous solutions

Abstract

Ectoine is an important osmolyte, which allows microorganisms to survive in extreme environmental salinity. The hygroscopic effects of ectoine in pure water can be explained by a strong water binding behavior whereas a study on the effects of ectoine in salty solution is yet missing. We provide Raman spectroscopic evidence that the influence of ectoine and NaCl are opposing and completely independent of each other. The effect can be explained by the formation of strongly hydrogen-bonded water molecules around ectoine which compensate the influence of the salt on the water dynamics. The mechanism is corroborated by first principles calculations and broadens our understanding of zwitterionic osmolytes in aqueous solution. Our findings allow us to provide a possible explanation for the relatively high osmolyte concentrations in halotolerant bacteria.

Characterizing modes of action and interaction for multicomponent osmolyte solutions on Jurkat cells

“…For example, SGC had more formulations with higher post‐thaw recovery than TGC under the same combination of glycerol and creatine, and our interaction models suggest the interaction of creatine to sucrose is stronger than it to trehalose. Interactions between sugars and amino acids are consistent to the work by Wen et al () that specific proteins stabilize trehalose during freezing and inhibit ice formation (Hahn, Uhlig, Solomun, Smiatek, & Sturm, ), that amino acids strengthen the local interactions between water molecules.…”

DNA protection by ectoine from ionizing radiation: molecular mechanisms

“…A similar ratio of 0.81 was obtained for ectoine and NaCl solution (data not shown) implying a negligible influence of NaCl on the scavenging capability of ectoine which is in agreement with our previous study on the combined influence of ectoine and salt on water. 8 …”

“…3 Ectoine, which has a zwitterionic structure ( Fig. 3) in the solid 4 state and in water, 5 exerts a kosmotropic effect on the local water structure [5][6][7][8] as well as an influence on protein functions. 7,[9][10][11] Moreover, various studies [12][13][14] investigated the effects of ectoine on biological damage caused by ultraviolet radiation (UV) of various wavelengths.…”

“…42 Ectoine, as a kosmotropic solute, influences strongly the water structure in its vicinity. [5][6][7][8]11 At a physiological ectoine concentration of about 1.6 M, approximately 80% of all water molecules are located within the first and second hydration shells of ectoine. 8 These water molecules are influenced in their interaction and vibrational behavior, which leads directly to a reduction of radiation damage as discussed above and agrees with the trend of the concentration dependent protection as displayed in Fig.…”

“…The published 39 energy loss dependent scattering intensity resamples the shape of the free vibrational density of states of water as displayed in Fig. 2 and the OH-modes of water 8,40 above 3050 cm À1 . The electron scattering cross-sections found by EELS in the region below 0.1 eV correspond to the Raman measurements in the range below o800 cm À1 (Fig.…”