Assembly of FtsZ was completely inhibited by low concentrations of urea and its unfolding occurred in two steps in the presence of urea, with the formation of an intermediate [Santra MK & Panda D (2003) J Biol Chem 278, 21336–21343]. In this study, using the fluorescence of 1-anilininonaph-thalene-8-sulfonic acid and far-UV circular dichroism spectroscopy, we found that a natural osmolyte, trimethylamine N-oxide (TMAO), counter-acted the denaturing effects of urea and guanidium chloride on FtsZ
