Chain A ( N76 L78 C79 S80 P81 R105 N106 A107 Y108 T109 P110 Q111 E112 I113 H142 C165 F167 Y170 D171 K173 A174 R175 H236 A237 I294 S295 K310 Q311 R386 F418 C489 N490 W491 A492 M494 I514 K516 K517 C518 L519 W520 S521 H522 )