Chain A ( F280 L288 S289 I290 D292 S294 H295 E296 G297 E298 G299 I300 P301 L302 D304 A305 C308 R354 T355 K356 N357 M358 W420 I421 E422 D424 A453 T454 E455 Y456 I457 M458 K459 G460 V461 Y462 I463 N464 T465 A466 L467 L468 N469 A470 S471 A473 Q479 L480 I481 P482 M483 I484 S485 K486 C487 K495 T496 N497 L498 Y499 G500 F501 I502 I503 K504 F518 T568 S569 K570 I571 K572 M573 K574 W575 G576 M577 E578 M579 R580 L583 L639 V643 )