Chain A ( L64 D65 S66 G68 K88 W98 A99 S100 Y101 S102 L103 E104 Y105 G106 K107 A108 E109 L110 V125 V126 D127 D128 L129 L130 A131 T132 G133 G134 T135 M136 N137 A138 A139 C140 E141 L142 L159 L162 K163 G164 K167 L168 )