!! calcium constraints

assign (resid  15 and name  OD1)   (resid  501 and resname  CA2)   2.500    0.800    0.300
assign (resid  30 and name  OD1 or resid 30 and name OD2)   (resid  501 and resname  CA2)   2.500    0.800    0.300
assign (resid  33 and name  OD1 or resid 33 and name OD2)   (resid  501 and resname  CA2)   2.500    0.800    0.300
