Fixed angle potential spring constant; didn't have a significant effect on persistence length

mrdna/segmentmodel.py

@@ -2423,7 +2423,7 @@ class SegmentModel(ArbdModel):
                     parent = self._getParent( b1, b2 )
 
                     """ Add heuristic 90 degree potential to keep orientation bead orthogonal """
-                    k = 0.5*k_dsdna_angle(sep)
+                    k = 0.25*k_dsdna_angle(sep)
                     pot = self.get_angle_potential(k,90)
                     parent.add_angle(o1,b1,b2, pot)
                     parent.add_angle(b1,b2,o2, pot)