Required for the sulfation of S881. S881 is a sulfated menaquinone, which is localized in the outer envelope of M.tuberculosis and negatively regulates its virulence. 3'-phosphoadenosine-5'-phosphosulfate (PAPS) is the sulfate donor. Deletion mutant does not synthesize S881 and shows a hypervirulent phenotype in the mouse model of infection. Belongs to the Stf3 family.