Chain A ( H225 R226 K227 S228 H229 S230 L231 D232 L233 E422 A424 E425 E426 K427 D428 S429 Y430 I431 C432 A433 V434 C435 L436 D437 V438 Y439 Y443 M444 C445 H449 H450 I451 F452 L457 L460 P469 C470 P471 L472 C473 R474 I477 Q483 E485 L486 A489 F493 F494 )