Chain A ( L13 A14 L15 G16 D17 S18 K22 V42 F81 L84 T85 F88 F89 R90 L97 M98 S106 N109 V110 W113 ),  Chain B ( T41 V42 G43 I44 W73 D74 T75 A76 G77 Q78 E79 R80 F81 R82 T85 )