Figure 1.

Overall structure of MtbCArgR. All subunits are shown as ribbon drawings and colored separately. (a) Superposition of apo (darker shade) and holo (lighter shade) hexamers viewed along a dyad symmetry axis. Only subunits D, E and F were used for structural alignment. The holo hexamer has six arginine molecules bound (two of them in this view are labeled R_A and R_D); these molecules are depicted by sticks with the C atoms in the color of the nearest subunit and with N and O atoms in blue and red, respectively. (b) Superposition as in (a) except viewed along the threefold symmetry axis from the top trimers with the bottom trimers removed for clarity. (c) The subunit of MtbCArgR has α/β topology (αββαββα).