Sequence homology between Lac and Gal repressors and three sugar-binding periplasmic proteins.
Many proteins consist of several independent folding units or domains, each specifying a different function. Repressor proteins such as Lac or lambda cI carry small N-terminal domains which recognize DNA sequences and larger C-terminal domains which are required for effector recognition and/or oligomerization. The native periplasmic metabolite-binding proteins consist of short membrane-recognizing signal sequences and larger C-terminal metabolite-binding domains which also recognize membrane-bound proteins involved in transport and chemotaxis. The DNA-recognizing domains of many repressors are homologous, as are the sugar-recognizing periplasmic proteins. Here I demonstrate that the sugar-binding domains of the Lac and Gal repressors are homologous with the sugar-binding domains of three periplasmic proteins.
D000595:Amino Acid Sequence; D001089:Arabinose / Q000378:metabolism; D001665:Binding Sites; D005075:Biological Evolution; D002352:Carrier Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D005690:Galactose / Q000378:metabolism; D007785:Lactose / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D012266:Ribose / Q000378:metabolism; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000378:metabolism*
D002352:Carrier Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D012266:Ribose; D001089:Arabinose; D007785:Lactose; D005690:Galactose