Interaction of ectoine and hydroxyectoine with protein: fuorescence study

Abstract

Ectoine and hydroxyectoine are well known extremolytes that accumulate in halophilic and halotolerant microorganisms. They are investigated as protein stabilizers and as excipients in protein formulations and biopharmaceuticals. However, their efect is quite controversial. In this work, the infuence of both extremolytes on mink growth hormone as a model protein was studied by fuorescence spectroscopy. The study revealed that the fuorescence quenching of protein tryptophan by ectoine and hydroxyectoine difers and is dependent on the pH value of solution. Moreover, the quenching mode by ectoine and hydroxyectoine was compared with a well-known quencher acrylamide. The diferences in the extremolytes interaction with protein revealed by fuorescence spectroscopy could be related to their diferent efect as protein stabilizers under various conditions. ectoine; hydroxyectoine; mink growth hormone; acrylamide; fluorescence quenching; sphere action static mechanism