Abstact

MabR (Rv2242), a PucR-type transcription factor, plays a crucial role in regulating mycolic acid biosynthesis in Mycobacterium tuberculosis. To understand its regulatory mechanisms, we determined the crystal structures of its N-terminal and C-terminal domains. The N-terminal domain adopts a globin-like fold, while the C-terminal domain comprises an α/β GGDEF domain and an all-α effector domain with a helix-turn-helix DNA-binding motif. This unique domain combination is specific to Actinomycetes. Biochemical and computational studies suggest that full-length MabR forms both dimeric and tetrameric assemblies in solution. Structural analysis revealed two distinct dimerization interfaces within the N- and C-terminal domains, further supporting a tetrameric organization. These findings provide valuable insights into the domain architecture, oligomeric state, and potential regulatory mechanisms of MabR.