Chain A ( D259 T260 S261 L262 A263 E264 G265 S266 V267 S268 C269 L362 V363 N364 K365 V366 L367 L368 V369 S412 T413 A414 Q415 I416 N419 I442 E444 C445 H446 H447 T448 N449 K450 E451 A452 V453 Y454 G494 H505 L509 Q576 Q580 F724 T725 K726 R728 L754 I755 G756 A757 G758 H759 S760 S761 F763 K764 P765 M766 Q768 Q771 V774 I775 A788 T789 T790 V791 A792 E793 E794 L796 R806 L809 V810 T811 N812 I814 A815 N847 K887 )