Chain A ( I669 Q675 L678 W682 Y683 N692 I695 I696 L699 P734 F735 V736 V737 F738 S739 W740 N741 V742 V743 F744 Y745 I746 A747 F748 L749 L750 L751 F752 A753 L778 D781 E782 R784 Q785 Y793 D796 L797 W798 N799 V800 M801 D802 T803 L804 G805 L806 D835 Y836 I838 F839 T840 L841 R842 L843 I844 H845 I846 F847 T848 V849 S850 R851 N852 L853 G854 P855 K856 I857 I858 M859 L860 Q861 R862 V993 W994 K995 F996 Q997 R998 Y999 F1000 L1001 V1002 Q1003 E1004 Y1005 C1006 S1007 R1008 L1009 I1011 P1012 F1013 I1016 Y1020 )