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A natural osmolyte trimethylamine N ‐oxide promotes assembly and bundling of the bacterial cell division protein, FtsZ and counteracts the denaturing effects of urea
Author(s) -
Mukherjee Arnab,
Santra Manas K.,
Beuria Tushar K.,
Panda Dulal
Publication year - 2005
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2005.04696.x
Subject(s) - ftsz , osmolyte , trimethylamine n oxide , chemistry , trimethylamine , biochemistry , gtpase , biophysics , guanidinium chloride , urea , cytoskeleton , crystallography , biology , cell , enzyme
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‐anilininonaphthalene‐8‐sulfonic acid and far‐UV circular dichroism spectroscopy, we found that a natural osmolyte, trimethylamine N ‐oxide (TMAO), counteracted the denaturing effects of urea and guanidium chloride on FtsZ. TMAO also protected assembly and bundling of FtsZ protofilaments from the denaturing effects of urea and guanidium chloride. Furthermore, the standard free energy changes for unfolding of FtsZ were estimated to be 22.5 and 28.4 kJ·mol −1 in the absence and presence of 0.6 m TMAO, respectively. The data are consistent with the view that osmolytes counteract denaturant‐induced unfolding of proteins by destabilizing the unfolded states. Interestingly, TMAO was also found to affect the assembly properties of native FtsZ. TMAO increased the light‐scattering signal of the FtsZ assembly, increased sedimentable polymer mass, enhanced bundling of FtsZ protofilaments and reduced the GTPase activity of FtsZ. Similar to TMAO, monosodium glutamate, a physiological osmolyte in bacteria, which induces assembly and bundling of FtsZ filaments in vitro [Beuria TK, Krishnakumar SS, Sahar S, Singh N, Gupta K, Meshram M & Panda D (2003) J Biol Chem 278 , 3735–3741], was also found to counteract the deleterious effects of urea on FtsZ. The results together suggested that physiological osmolytes may regulate assembly and bundling of FtsZ in bacteria and that they may protect the functionality of FtsZ under environmental stress conditions.