Cell division in bacteria is initiated and guided to completion by the FtsZ protein, which is the prokaryotic homologue of tubulin. In comparison with FtsZ homologues from fast growing bacterial species like E. coli, the M. tuberculosis FtsZ is known to undergo slow polymerization. This in turn accommodates the slow growth properties of this pathogenic bacillus and has probably co-evolved with the slow DNA and RNA polymerases in this organism. Using molecular biological, biochemical, immunological, microscopic and biophysical techniques the slow polymerization property of M. tuberculosis FtsZ homologue was investigated. The determinant(s) for slow polymerization was localized to the C-terminus of the protein. A hitherto unknown oligomeric state of FtsZ was discovered and its response to GTP binding studied by dynamic light scaterring. During overexpression and purification, the M. tuberculosis FtsZ protein underwent dimerisation, which is mediated by a lone cysteine. Dimerisation locks two monomers with non-complementary domains facing each other. This property was exploited to compare the GTP binding, GTPase and polymerization activities of the dimeric and monomeric forms of the protein. GTP hydrolysis and polymerization are dependent on oligomerisation of the protein. This property along with the functional overlap of the domains and their regulatory role in polymerization was used to arrive at a model for FtsZ polymerization.