Chain A ( L704 G721 A722 F723 G724 V726 A743 K745 L747 E749 T751 E758 I759 L760 D761 E762 A763 Y764 V765 M766 A767 V769 V774 C775 L777 G779 I780 C781 L782 V786 Q787 L788 I789 T790 L792 M793 C797 H835 R836 D837 L838 A839 A840 R841 N842 V843 L844 V845 V851 K852 I853 T854 D855 F856 G857 L858 A859 K860 L861 L862 K875 P877 W880 E906 )