Structural biology leverages the three-dimensional shape assumed by macromolecules like proteins and nucleic acids to understand the function and evolutionary history of the molecule. We use X-ray crystallography to determine the atomic resolution structures of Mtb proteins, alone and in complex with other proteins, natural ligands, and inhibitors. Practical applications of this endeavor include the manipulation and inhibition of protein function by the rational design of small molecule ligands. The resulting functional modulators can be used to probe the physiological roles of proteins in the intact cell, and can serve as leads for the development of new therapeutics. Multiple structures and small molecule inhibitors developed by the TBSGC are driving current TB drug discovery efforts.