DHFR GI:4503323 dihydrofolate reductase 1 mvgslnciva vsqnmgigkn gdlpwpplrn efryfqrmtt tssvegkqnl 50 51 vimgkktwfs ipeknrplkg rinlvlsrel keppqgahfl srslddalkl 100 101 teqpelankv dmvwivggss vykeamnhpg hlklfvtrim qdfesdtffp 150 151 eidlekykll peypgvlsdv qeekgikykf evyeknd