PitA is a low-affinity transporter for inorganic phosphate. It imports phosphate complexed to divalent cations such as Mg(2+) or Ca(2+). Loss of PitA function can confer reduced sensitivity to high levels of Zn(2+). The PitA of Escherichia coli has a closely related paralog, PitB, that is functional but only minimally expressed. Note that the term PitA is used broadly. This exception-level HMM identifies a rather narrow clade of PitA transporters which, however, includes both PitA and PitB of E. coli K-12.
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