Original sentence: Each functional P2X receptor is a trimer, with the three protein subunits arranged around an ion-permeable channel pore.To date, seven separate genes coding for P2X subunits have been identified, and referred to as P2X1 through P2X7
Edited sentence: Evidence from early molecular biological and functional studies has strongly indicated that the functional P2X receptor protein is a trimer, with the three peptide subunits arranged around an ion-permeable channel pore.This view was recently confirmed by the use of X-ray crystallography to resolve the three-dimensional structure of the zebrafish P2X4 receptor.To date, seven separate genes coding for P2X subunits have been identified, and named to as P2X1 through P2X7