Chain A ( F63 I68 S69 W95 T96 I97 R98 L99 E107 G108 L109 S110 Y111 T112 S113 D114 T115 P116 F117 I118 G225 G226 V227 L462 G465 G466 I467 D468 W469 G470 N508 N511 H512 P513 Q514 S515 I516 )