This domain is found at the N-terminus of the Polyhydroxyalkanoate (PHA) synthesis regulators. These regulators have been shown to directly bind DNA and PHA ([1]). The invariant nature of this domain compared to the C-terminal Pfam:PF05233 domain(s) suggests that it contains the DNA-binding function.

1: A repressor protein, PhaR, regulates polyhydroxyalkanoate (PHA) synthesis via its direct interaction with PHA. Maehara A, Taguchi S, Nishiyama T, Yamane T, Doi Y; J Bacteriol 2002;184:3992-4002. PMID:12081972