Practice question

Cytoskeletal homology across domains revealed by structural biology although sequence similarity low. FtsZ protein essential division highly conserved tubulin homolog. Crystal structures show globular N terminal domain with Rossmann fold GTPase active site containing T1 to T6 loops coordinating GTP plus magnesium, H7 helix central, C terminal domain involved filament contacts. Organization identical to alpha beta tubulin dimer architecture. Both polymerize head to tail forming protofilaments, binding GTP promotes assembly, hydrolysis to GDP promotes disassembly causing dynamic instability. Tubulin assembles hollow microtubules 13 protofilaments lateral contacts forming 25 nanometer tube providing tracks for kinesin dynein motors and spindle fibers. FtsZ forms single stranded protofilaments bundling into Z ring at midcell scaffolding peptidoglycan synthases. MreB actin homolog and Crescentin intermediate filament like are other bacterial cytoskeletal types but tubulin homolog uniquely FtsZ. Therefore bacterial protein list identifies FtsZ as tubulin counterpart, essential gene, target for antimicrobial PC190723, chlorinated benzamide derivatives disrupting GTPase and filament assembly blocking cytokinesis causing filamentous nonviable cells.