Chain A ( K529 Q530 I531 G532 S533 G534 S537 K538 V539 F540 Q541 V542 Y550 A551 I552 K553 Y554 Y568 I572 L575 I586 M600 M602 E603 C604 G605 N606 I607 D608 N610 S611 K649 P650 A651 N652 F653 L654 K661 L662 I663 D664 N669 Q670 M671 Q672 P673 D674 T675 )