HelixConstraint A28 L31 0.887 StrandConstraint C40 V41 0.644 HelixConstraint L74 M81 0.664 HelixConstraint R101 Y109 0.604 HelixConstraint S117 Q123 0.659 HelixConstraint N135 Q143 0.78 HelixConstraint Y145 T148 0.701