Proteins in this family have a HotDog fold. This family was formerly known as domain of unknown function 2662 (DUF2662). The structure of Rv0098 from M. tuberculosis suggested a thioesterase function. Assays showed that this protein was a thioesterase with a preference for long chain fatty acyl groups. The maximal Kcat was observed for palmitoyl-CoA although longer and shorter molecules were also cleaved. In solution this protein forms a homo-hexameric complex.