Chain A ( A12 I13 C14 A15 C17 R37 G38 L39 G40 N41 K42 G43 T44 L45 P46 W47 C49 N50 S51 V52 D53 M54 Y56 F57 S58 V60 T61 M113 G114 R115 S116 S117 W118 S120 I121 P122 Y125 P127 L128 R131 N133 V135 I172 I173 G174 G175 A176 V178 Y179 C202 D203 V204 F205 F206 )