Chain A ( S17 G18 N36 K37 E40 R59 F83 G84 G85 S86 V87 R88 S89 E90 E92 L93 A95 ),  Chain B ( I681 N682 V685 S725 F727 D756 R757 I758 G759 G760 D761 Q762 G763 K764 Y765 L766 A775 S776 W777 R780 L782 H783 T785 S786 L787 R788 D789 P790 Y791 H792 A793 Y794 K834 V835 E836 E837 L838 I839 R840 R845 Q846 )