The amino acid sequences of ORCOs are highly conserved among insects mostly those residues implicated in the tetrameric pore and the compact membrane anchors. For instance, residues implicated in VUAA-binding to the central tetrameric pore, such as K86-D213, and D213-N392, are highly conserved Except Ca ++ or Mg ++ , most cations may flow through the pore in the presence of VUAA1, however, mutations at pore residues such as V469 and/or L473, resulted in 10-fold enhancements of VUAA1-binding and allowed Ca ++ flow.