A change of threonine 266 to isoleucine in the lac permease of Escherichia coli diminishes the transport of lactose and increases the transport of maltose.
The DNA sequence of several functionally interesting lac permease mutants of Escherichia coli has been determined. The phenotypes of the mutant permeases were described by Mieschendahl et al. (1981). The following exchanges are noteworthy: tyr to asp in codon 26 in Y-K MUB 7; thr to ile in codon 266 in Y-K AJ 33; gly to asp in codon 262 in Y-D 3 and in Y-D 4.
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology; D001483:Base Sequence; D003062:Codon; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D007785:Lactose / Q000378:metabolism*; D008320:Maltose / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000502:physiology; D009004:Monosaccharide Transport Proteins; D027981:Symporters
D001426:Bacterial Proteins; D003062:Codon; D029968:Escherichia coli Proteins; C050221:LacY protein, E coli; D026901:Membrane Transport Proteins; D009004:Monosaccharide Transport Proteins; D027981:Symporters; D008320:Maltose; C021499:lactose permease; D007785:Lactose