Rv0802c from Mycobacterium tuberculosis: the first structure of a succinyltransferase with the GNAT fold

Gene rv0802c from Mycobacterium tuberculosis encodes a 218-amino-acid protein and is annotated as a hypothetical protein with homology to GCN5-related N-acetyltransferases. The structure of Rv0802c was determined in an unliganded form to 2.0 Å resolution utilizing single-wavelength anomalous dispersion from a samarium soak that resulted in a single bound Sm³⁺:citrate² complex. The structure confirms that Rv0802c exhibits the GCN5-related N-­acetyltransferase fold and revealed a tetramer composed of a dimer of dimers with approximate 222 symmetry. In addition, a bound acetate ion indicated that Rv0802c may utilize a unique acyl donor for the family. The subsequent determination of the structure of Rv0802c in complex with succinyl-CoA to 2.3 Å resolution suggests that Rv0802c is the first known GCN5-related N-­acetyltransferase family member to utilize succinyl-CoA as a substrate.