Zusammenfassung
Ectoine is a widespread osmolyte enabling halophilic bacteria to withstand high osmotic stress that has many potential applications ranging from cosmetics to its use as a therapeutic agent. In this contribution, combining expt. and theory, the hydration and ion-binding of this zwitterionic compd. was studied to gain information on the functioning of ectoine in particular and of osmolytes in ...
Zusammenfassung
Ectoine is a widespread osmolyte enabling halophilic bacteria to withstand high osmotic stress that has many potential applications ranging from cosmetics to its use as a therapeutic agent. In this contribution, combining expt. and theory, the hydration and ion-binding of this zwitterionic compd. was studied to gain information on the functioning of ectoine in particular and of osmolytes in general. Dielec. relaxation spectroscopy was used to det. the effective hydration no. of ectoine and its effective dipole moment in aq. solns. with and without added NaCl. The obtained exptl. data were compared with structural results from 1D-RISM and 3D-RISM calcns. It was found that ectoine is strongly hydrated, even in the presence of high salt concns. Upon addn. of NaCl, ions are bound to ectoine but the formed complexes are not very stable. Interestingly, this osmolyte strongly rises the static relative permittivity of its solns., shielding thus effectively long-range Coulomb interactions among ions in ectoine-contg. solns. We believe that via this effect, which should be common to all zwitterionic osmolytes, ectoine protects against excessive ions within the cell in addn. to its strong osmotic activity protecting against ions outside.