Conservation of residues involved in sugar/H(+) symport by the sucrose permease of Escherichia coli relative to lactose permease.
Building a three-dimensional model of the sucrose permease of Escherichia coli (CscB) with the X-ray crystal structure lactose permease (LacY) as template reveals a similar overall fold for CscB. Moreover, despite only 28% sequence identity and a marked difference in substrate specificity, the structural organization of the residues involved in sugar-binding and H(+) translocation is conserved in CscB. Functional analyses of mutants in the homologous key residues provide strong evidence that they play a similar critical role in the mechanisms of CscB and LacY.
Department of Physiology and Microbiology, Immunology and Molecular Genetics, Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA 90095-7327, USA.
Viveka
V
Vadyvaloo
Irina N
IN
Smirnova
Vladimir N
VN
Kasho
H Ronald
HR
Kaback
D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D050260:Carbohydrate Metabolism; D017124:Conserved Sequence; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005798:Genes, Bacterial; D006859:Hydrogen / Q000378:metabolism; D007700:Kinetics; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D009004:Monosaccharide Transport Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D027981:Symporters / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D029968:Escherichia coli Proteins; C050221:LacY protein, E coli; D026901:Membrane Transport Proteins; D009004:Monosaccharide Transport Proteins; D011994:Recombinant Proteins; D027981:Symporters; C056379:cscB protein, E coli; D006859:Hydrogen