Phosphate metabolism in H. walsbyi. Scheme revealing the proteins involved in phosphate metabolism. The transporters PitA1-3, Phn2ECD, PstABC and phosphate storage enzyme polyphosphate kinase (Ppk) are common in several haloarchaea. Unique to H. walsbyi are the bacterial-type proteins involved in phosphonate metabolism, an ABC-type phosphonate uptake system plus phosphonate lyase, and the PTS dependent dihydroxyacetone kinase (DHAK). DHA, dihydroxyacetone; DHAP, dihydroxyacetone phosphate; Pi, phosphate ion; PEP, phospho enol pyruvate; PL, phospholipid.