This region is found in the C-terminus of a number of archaeal transcriptional regulators. It is thought to function as a metal-sensing regulatory module [1].

1: TRASH: a novel metal-binding domain predicted to be involved in heavy-metal sensing, trafficking and resistance. Ettema TJ, Huynen MA, de Vos WM, van der Oost J; Trends Biochem Sci 2003;28:170-173. PMID:12713899