Conformational changes upon ligand binding in the essential class II fumarase Rv1098c from Mycobacterium tuberculosis

► M. tuberculosis fumarase complexes with l-malate, meso-tartrate or fumarate. ► First reported crystal structure of a fumarase in complex with fumarate. ► Substrate binding leads to active site closure, sequestering from solvent. ► Experimental evidence suggests His187 and Ser318 as the acid-base catalysts.