HelixConstraint V28 V30 0.61 HelixConstraint I58 K71 0.755 HelixConstraint I96 L99 0.627 HelixConstraint W109 S113 0.726 HelixConstraint A120 T127 0.631 HelixConstraint W155 N159 0.64 StrandConstraint I168 L170 0.671