1.2.1.61 C281A site-directed mutagenesis 742206 1.2.1.61 E247K site-directed mutagenesis 742206 1.2.1.61 F150A site-directed mutagenesis 742206 1.2.1.61 F154A site-directed mutagenesis 742206 1.2.1.61 F447A site-directed mutagenesis 742206 1.2.1.61 H275E site-directed mutagenesis 742206 1.2.1.61 I282D site-directed mutagenesis 742206 1.2.1.61 N149A site-directed mutagenesis 742206 1.2.1.61 W157A site-directed mutagenesis 742206