Chain A ( R44 L45 S46 G171 I172 N173 R174 C175 V176 A177 I178 C179 F180 Y181 R182 T183 R184 A185 K186 T187 N189 R190 V191 C259 V263 K266 I267 V270 R271 K273 S283 R286 F287 K288 Q290 N435 T436 A437 N438 E439 S441 E442 G443 W444 T445 E446 S447 S448 T451 E452 A453 M479 )