Chain A ( M340 G510 L511 L514 D533 T534 D538 R598 S600 T605 Y606 N609 S661 G662 D663 D664 K689 P707 F708 C709 S710 H711 F713 P727 R729 E733 L734 R737 Y758 M761 W762 Y766 R792 T793 T794 W795 S796 I797 H798 A799 H800 H801 )