Chain B ( F58 A61 Y64 L87 K90 M92 V112 S113 A114 E115 E116 A117 Y118 K119 H120 L121 T122 F126 I131 Y132 L139 L150 P193 T196 D225 F228 T229 P230 I231 N232 F233 V234 F235 P236 G303 I304 M306 G307 G308 Q309 H310 T311 S312 A313 S314 T315 A317 W318 L370 H373 M374 P375 L376 H377 S378 I379 F380 R381 K382 V383 Y401 P462 F463 G464 G465 H468 R469 C470 I471 G472 E473 D504 Y505 S506 S507 M508 V509 V510 L511 )