This is a domain with a GCN5-related N-acetyltransferase (GNAT) fold which can be found in Rv1692 phophatases. Crystal structure of Rv1692 indicates that this C-temrinal extension, which is absent in other characterized HADSF members, resembles a small GCN5-related N-acetyltransferase (GNAT) fold. Furthermore, it is fused to the HADSF catalytic domain Pfam:PF13242 . Functional studies indicate that this GNAT region is not likely to be involved in acetyl group transfer using AcCoA and SucCoA, it could nonetheless be a regulatory domain. Furthermore, it is suggested that this GNAT domain is required for the solubility of the HADSF fold of Rv1692 and is potentially needed for the structural integrity of this enzyme [1].

1: Discovery of a glycerol 3-phosphate phosphatase reveals glycerophospholipid polar head recycling in Mycobacterium tuberculosis. Larrouy-Maumus G, Biswas T, Hunt DM, Kelly G, Tsodikov OV, de Carvalho LP; Proc Natl Acad Sci U S A. 2013;110:11320-11325. PMID:23801751