title: Glycerol facilitator GlpF and the associated aquaporin family of channels.
abstract: The aqua (glycero) porins conduct water (and glycerol) across cell membranes. The structure of these channels reveals a tripathic channel that supports a hydrophobic surface and, opposite to this, a line of eight hydrogen-bond acceptors and four hydrogen-bond donors. The eight carbonyls act as acceptors for water (or glycerol OH) molecules. The central water molecule in the channel is oriented to polarize hydrogen atoms outward from the center. This arrangement suggests how the structure prevents the potentially lethal conduction of protons across the membrane. The structure also suggests the mechanism behind the selectivity of aquaglyceroporins for glycerol, the basis for enantioselectivity among alditols, and the basis for the prevention of any leakage of the electrochemical gradient.
authors.affiliation: Department of Biochemistry & Biophysics, School of Medicine, 600 16th Street, University of California San Francisco, CA 94143-2240, USA. stroud@msg.ucsf.edu
authors.forename: Robert M
authors.initials: RM
authors.lastname: Stroud
authors.forename: Larry J W
authors.initials: LJ
authors.lastname: Miercke
authors.forename: Joseph
authors.initials: J
authors.lastname: O'Connell
authors.forename: Shahram
authors.initials: S
authors.lastname: Khademi
authors.forename: John K
authors.initials: JK
authors.lastname: Lee
authors.forename: Jonathan
authors.initials: J
authors.lastname: Remis
authors.forename: William
authors.initials: W
authors.lastname: Harries
authors.forename: Yaneth
authors.initials: Y
authors.lastname: Robles
authors.forename: David
authors.initials: D
authors.lastname: Akhavan
mesh_terms: D020346:Aquaporins / Q000737:chemistry / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism*; D007477:Ions / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011522:Protons; D014867:Water / Q000378:metabolism
chemical_list: D020346:Aquaporins; D029968:Escherichia coli Proteins; D007477:Ions; D011522:Protons; D014867:Water; C078043:GlpF protein, E coli; D005990:Glycerol