Chain A ( I26 G27 S30 G32 V34 K36 V46 A47 I48 K49 I51 E66 L70 T79 I93 I94 M95 E96 Y97 L98 G100 G101 S102 K142 A144 N145 L147 L148 K155 A157 D158 F159 )