Cloning, expression, purification and crystallization of a transcriptional regulatory protein (Rv3291c) from Mycobacterium tuberculosis H37Rv

Rv3291c, the translational product of the Mycobacterium tuberculosis Rv3291c gene, is an 18 kDa protein. It is a putative transcriptional regulatory protein belonging to the leucine-responsive regulatory protein/asparagine synthase C (Lrp/AsnC) family, which are proteins that have been identified in archaea and bacteria. Rv3291c probably plays a significant role during the persistent/latent phase of M. tuberculosis, as supported by its up-regulation several-fold during this stage. Orthorhombic crystals of recombinant Rv3291c have been grown from trisodium citrate dihydrate-buffered solutions containing monoammonium dihydrogen phosphate. Diffraction data extending to 2.7 Angstrom have been collected from a single crystal with unit-cell parameters a = 99.6, b = 100.7, c = 100.6 Angstrom. Assuming an octamer in the asymmetric unit results in a Matthews coefficient (V-M) of 1.75 Angstrom(3) Da(-1), corresponding to a solvent content of about 30%.