colvar {
    name distance

    distance {
        group1 {
            psfSegID PROA
            atomNameResidueRange CA 1-200
        }
        group2 {
            psfSegID PROB
            atomNameResidueRange CA 1-150
        }
    }
}

colvar {
 name pull_chainA_x
 distanceZ {
   main {
     psfSegID PROA
     atomNameResidueRange CA 1-200
   }
   ref {
     dummyAtom (12.8345741, -0.494435275, -0.488736064)
   }
   axis (-1.0, 0.0, 0.0)
   forceNoPBC yes
 }
}

colvar {
 name pull_chainA_y
 distanceZ {
   main {
     psfSegID PROA
     atomNameResidueRange CA 1-200
   }
   ref {
     dummyAtom (12.8345741, -0.494435275, -0.488736064)
   }
   axis (0.0, 1.0, 0.0)
   forceNoPBC yes
 }
}

colvar {
 name pull_chainA_z
 distanceZ {
   main {
     psfSegID PROA
     atomNameResidueRange CA 1-200
   }
   ref {
     dummyAtom (12.8345741, -0.494435275, -0.488736064)
   }
   axis (0.0, 0.0, 1.0)
   forceNoPBC yes
 }
}

colvar {
 name pull_chainB_x
 distanceZ {
   main {
     psfSegID PROB
     atomNameResidueRange CA 1-150
   }
   ref {
     dummyAtom (-34.6032023, -1.12537024, 0.385760331)
   }
   axis (1.0, 0.0, 0.0)
   forceNoPBC yes
 }
}

colvar {
 name pull_chainB_y
 distanceZ {
   main {
     psfSegID PROB
     atomNameResidueRange CA 1-150
   }
   ref {
     dummyAtom (-34.6032023, -1.12537024, 0.385760331)
   }
   axis (0.0, 1.0, 0.0)
   forceNoPBC yes
 }
}

colvar {
 name pull_chainB_z
 distanceZ {
   main {
     psfSegID PROB
     atomNameResidueRange CA 1-150
   }
   ref {
     dummyAtom (-34.6032023, -1.12537024, 0.385760331)
   }
   axis (0.0, 0.0, 1.0)
   forceNoPBC yes
 }
}

## Harmonics to pull
harmonic {
   colvars       pull_chainA_x   pull_chainA_y pull_chainA_z pull_chainB_x pull_chainB_y pull_chainB1_z
   centers       -20.0           0.0           0.0           20.0          0.0           0.0
   targetCenters -20.5           0.0           0.0           20.5          0.0           0.0
   forceConstant 5.
   targetNumSteps 500000
}
