title: The alternating access transport mechanism in LacY.
abstract: Lactose permease of Escherichia coli (LacY) is highly dynamic, and sugar binding causes closing of a large inward-facing cavity with opening of a wide outward-facing hydrophilic cavity. Therefore, lactose/H(+) symport via LacY very likely involves a global conformational change that allows alternating access of single sugar- and H(+)-binding sites to either side of the membrane. Here, in honor of Stephan H. White's seventieth birthday, we review in camera the various biochemical/biophysical approaches that provide experimental evidence for the alternating access mechanism.
authors.affiliation: Department of Physiology, University of California Los Angeles, Los Angeles, CA 90095, USA. rkaback@mednet.ucla.edu
authors.forename: H Ronald
authors.initials: HR
authors.lastname: Kaback
authors.forename: Irina
authors.initials: I
authors.lastname: Smirnova
authors.forename: Vladimir
authors.initials: V
authors.lastname: Kasho
authors.forename: Yiling
authors.initials: Y
authors.lastname: Nie
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D000478:Alkylation; D001692:Biological Transport / Q000502:physiology*; D003545:Cysteine / Q000737:chemistry; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D009004:Monosaccharide Transport Proteins / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation; D027981:Symporters / Q000737:chemistry / Q000378:metabolism*; D014364:Tryptophan / Q000737:chemistry
chemical_list: D029968:Escherichia coli Proteins; C050221:LacY protein, E coli; D009004:Monosaccharide Transport Proteins; D027981:Symporters; D014364:Tryptophan; D003545:Cysteine