title: WhmD promotes the assembly of Mycobacterium smegmatis FtsZ: A possible role of WhmD in bacterial cell division.
abstract: WhmD is considered to have a role in the septation and division of Mycobacterium smegmatis cells. Since FtsZ is the central protein of the septum, we determined the effect of WhmD on the assembly of Mycobacterium smegmatis FtsZ (MsFtsZ) in vitro. WhmD increased both the rate and extent of the assembly of MsFtsZ in vitro. WhmD also increased the amount of polymerized MsFtsZ as evident from a sedimentation assay. Further, the assembly promoting activity of WhmD occurred in the presence of GTP. MsFtsZ polymerized to form thin filaments in the absence of WhmD while MsFtsZ formed thick filaments in the presence of WhmD suggesting that WhmD enhanced the bundling of MsFtsZ filaments. Interestingly, WhmD neither suppressed the dilution-induced disassembly of FtsZ filaments nor significantly altered the GTPase activity of FtsZ. Using size exclusion chromatography, circular dichroism and fluorescence spectroscopy, WhmD was found to bind to MsFtsZ in vitro. The results showed that WhmD can promote the assembly of FtsZ and indicated that WhmD may play a role in the division of M. smegmatis cells by assisting the polymerization of FtsZ.
authors.affiliation: Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India.
authors.forename: Dipanwita
authors.initials: D
authors.lastname: Bhattacharya
authors.affiliation: Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India. Electronic address: ashutoshk@iitb.ac.in.
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, India. Electronic address: panda@iitb.ac.in.
authors.forename: Dulal
authors.initials: D
authors.lastname: Panda
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D002455:Cell Division; D003598:Cytoskeletal Proteins / Q000737:chemistry*; D020558:GTP Phosphohydrolases / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D020102:Mycobacterium smegmatis / Q000166:cytology* / Q000378:metabolism; D011489:Protein Denaturation; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; C071525:FtsZ protein, Bacteria; C412372:WhmD protein, Mycobacterium smegmatis; D006160:Guanosine Triphosphate; D020558:GTP Phosphohydrolases
keywords: Bundling; Polymerization; Septum; Z-ring