Crystallization of the Mycobacterium tuberculosis cell-division protein FtsZ

Mycobacterium tuberculosis FtsZ (MtbFtsZ), an essential protein in bacterial cell division, has been crystallized in the presence of a new inhibitor of MtbFtsZ polymerization and GTPase activity, ethyl (6-­amino-2,3-dihydro-4-phenyl-1H-pyrido[4,3-b][1,4]diazepin-8-yl)carbamate (SRI-7614). Crystals of the MtbFtsZ–SRI-7614 complex (form I, 30% polyethylene glycol 4000, 0.1 M sodium citrate pH 5.6, 0.2 M NH₄OAc, 293 K) belong to space group P6₁ or P6₅, with unit-cell parameters a = 88.78, c = 178.02 Å, and diffract to 2.3 Å resolution. A second crystal form, of the GDP complex, grows in the presence or absence of Mg²⁺ from PEG 4000 at 277 K or from (NH₄)₂SO₄ at 293 K, respectively (form II, space group P6₂22 or P6₄22, with unit-cell parameters a = 135.02, c = 328.97 Å or a = 129.30, c = 327.97 Å, respectively). Complete data sets to ∼7 Å resolution have been collected from both. Exceptional form II crystals diffract to at least 4.5 Å resolution. Determination of the MtbFtsZ structure may advance the design of improved inhibitors of FtsZ polymerization.