tailieunhanh - Báo cáo khoa học: A natural osmolyte trimethylamine N-oxide promotes assembly and bundling of the bacterial cell division protein, FtsZ and counteracts the denaturing effects of urea

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 | iFEBS Journal A natural osmolyte trimethylamine W-oxide promotes assembly and bundling of the bacterial cell division protein FtsZ and counteracts the denaturing effects of urea Arnab Mukherjee Manas K. Santra Tushar K. Beuria and Dulal Panda Schoolof Biosciences and Bioengineering Indian Institute of Technology Bombay Mumbai India Keywords FtsZ FtsZ unfolding osmolyte protofilaments bundling TMAO Correspondence D. Panda Schoolof Biosciences and Bioengineering Indian Institute of Technology Bombay Powai Mumbai 400076 India Fax 91 22 2572 3480 Tel 91 22 2576 7838 E-mail panda@ Received 27 December 2004 revised 24 February 2005 accepted 1 April 2005 doi 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 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 and kJ-mol-1 in the absence and presence of 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 .