Chain A ( T14 L15 G16 E17 A19 Y20 G21 E22 V23 Q24 L25 V35 A36 V37 K38 I39 V40 E55 I68 Y71 L82 F83 M84 E85 L86 A87 S88 G89 G90 S91 L92 H134 L136 L137 K145 I146 A147 D148 Y149 )