Slow polymerization of Mycobacterium tuberculosis FtsZ

The essential cell division protein. FtsZ, from Mycobacterium tuberculosis has been expressed in Escherichia coli and purified. The recombinant protei n has GTPase activity typical of tubulin and other FtsZs. FtsZ polymerizati on was studied using 90 degrees light scattering. The mycobacterial protein reaches maximum polymerization much more slowly (similar to 10 min) than E . coli FtsZ. Depolymerization also occurs slowly, taking 1 h or longer unde r most conditions. Polymerization requires both Mg2+ and GTP, The minimum c oncentration of FtsZ needed for polymerization is 3 mu M. Electron microsco py shows that polymerized M. tuberculosis FtsZ consists of strands that ass ociate to form ordered aggregates of parallel protofilaments. Ethyl 6-amino -2,3-dihydro-4-phenyl-1H-pyrido [4,3-b] [1,4] diazepin-8-ylcarbamate (SRI 7 614), an inhibitor of tubulin polymerization synthesized at Southern Resear ch Institute, inhibits M. tuberculosis FtsZ polymerization, inhibits GTP hy drolysis, and reduces the number and sizes of FtsZ polymers.