Chain A ( Y553 C670 Q671 P672 I673 F674 L675 N676 V677 L678 E679 A680 I681 E682 P683 G684 V685 V686 Q712 W719 L723 P724 L745 F748 A749 M750 G751 W752 R753 S754 F755 T756 N757 Y764 F765 F795 I800 T801 P802 Q803 E804 F805 L806 C807 M808 K809 A810 L811 L812 L813 F814 Y835 L839 I842 L860 L863 L864 )