Chain A ( D10 R11 L12 R13 L14 P15 Y136 K140 R194 I257 F258 M259 T260 V261 V262 Y263 F264 G265 P266 L267 T268 C269 S270 I271 I272 L309 D310 A311 F313 G314 K315 G316 K318 )