Chain A ( D49 L50 R51 C52 Y53 R54 Y60 E61 C62 S63 W64 F99 V111 L113 V129 T130 L131 Q132 L133 N135 S136 V137 K138 Y139 Q214 S217 Q218 G219 S220 S221 W222 S223 K224 )