Purification, crystallization and preliminary X-ray analysis of Mycobacterium tuberculosis folylpolyglutamate synthase (MtbFPGS)

The gene encoding Mycobacterium tuberculosis FPGS (MtbFPGS; Rv2447c) has been cloned and the protein (51 kDa) expressed in Escherichia coli. The purified protein was crystallized either by the batch method in the presence of adenosine diphosphate (ADP) and CoCl₂ or by vapour diffusion in the presence of ADP, dihydrofolate and CaCl₂. X-ray diffraction data to approximately 2.0 and 2.6 Å resolution were collected at the Stanford Synchrotron Radiation Laboratory (SSRL) for crystals grown under the respective conditions. Both crystals belong to the cubic space group P2₁3, with a unit-cell parameter of 112.6 and 111.8 Å, respectively. Structure determination is proceeding.