Mutational and structural study of RipA, a key enzyme in Mycobacterium tuberculosis cell division: evidence for the L-to-D inversion of configuration of the catalytic cysteine

RipA is a key cysteine protease of Mycobacterium tuberculosis as it is responsible for bacterial daughter-cell separation. By combining crystallographic and mutational studies with functional assays and molecular modelling, it is shown that the catalytic activity of the enzyme relies on a Cys-His-Glu triad. The impact of the mutation of each residue of the triad on the structure and function of RipA is also analysed.