Chain A ( H244 R247 L258 H262 Y315 Q319 I323 D495 L499 Y506 A550 I557 R558 L559 A560 T561 L562 E563 L564 C566 L567 K570 D612 M613 F614 E615 D616 E617 Y618 R619 S620 M621 T622 M623 K624 P625 M626 N627 V628 E629 Y630 L631 M632 M633 D634 A635 S636 I637 L638 L639 P640 P641 T642 P645 L646 T647 G648 I649 D650 F651 V652 K653 R654 L655 R664 R665 I667 R668 V669 F670 F671 M672 L673 R674 S675 L676 Q679 Q756 D757 K776 P777 A778 S779 S780 P781 H782 S783 S982 S1006 L1007 T1008 L1009 V1010 P1011 P1012 V1013 D1014 P1015 H1016 S1017 L1018 R1019 S1020 L1021 T1022 )