Chain A ( F325 D326 Q327 V328 R329 L330 L331 E332 S333 C334 E337 I404 L405 N407 S408 S409 M410 Y411 P412 L413 V414 Q418 D419 S423 R466 E493 M494 L495 N496 A497 H498 V499 L500 R501 G502 K504 S505 )