Chain A ( R4 S6 S7 G8 E9 H14 L15 R38 A40 T41 I45 E76 E80 F82 D84 T86 R87 R88 L89 C90 D91 L92 R93 R115 E116 F119 W669 L699 K700 L702 N703 R704 Q705 V706 E707 A708 M709 E710 K711 N714 D743 F744 M745 D746 A747 L748 L764 )