Atomic structure of a glycerol channel and implications for substrate permeation in aqua(glycero)porins.
The structure of a glycerol channel from Escherichia coli at 2.2 A resolution serves as a basis for the understanding of selective transmembrane substrate permeation. In the course of permeation, glycerol molecules diffuse through a tripathic channel with their alkyl backbone wedged against a hydrophobic corner, such that OH groups become acceptors and donors of hydrogen bonds at the same time. The structure of the channel explains the preferential permeability for linear carbohydrates and absolute exclusion of ions and charged solutes. Its gene-duplicated sequence has a structural counterpart in a pseudo two-fold symmetry within the monomeric channel protein.
Nollert
P
P
Department of Biochemistry and Biophysics, School of Medicine, University of California, San Francisco, CA94143-0448, USA.
Harries
W E
WE
Fu
D
D
Miercke
L J
LJ
Stroud
R M
RM
D000595:Amino Acid Sequence; D020346:Aquaporins / Q000737:chemistry* / Q000378:metabolism*; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry*; D002241:Carbohydrates / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins; D005990:Glycerol / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D020346:Aquaporins; D001425:Bacterial Outer Membrane Proteins; D002241:Carbohydrates; D029968:Escherichia coli Proteins; D007477:Ions; C078043:GlpF protein, E coli; D005990:Glycerol