The structure of GlpF, a glycerol conducting channel.

摘要: The passage of water or small neutral solutes across the cell membrane in animals, plants and bacteria is facilitated by a family homologous channels, variously known as aquaporins though perhaps more correctly aquaglyceroporins. glycerol facilitator (GlpF) 28 kDa aquaglyceroporin that catalyses transmembrane diffusion certain linear polyhydric alcohols Escherichia coli. X-ray crystallographic analysis GlpF to 2.2 A resolution revealed an alpha-barrel structure, surrounded six full-length helices two half-spanning are joined head-to-head middle membrane. These arranged quasi twofold manner relative central plane, where highly conserved residues make helix-to-helix contacts stabilize position orientation structure. This sequence-structure correlation suggests evolutionary divergence aquaglyceroporins constrained structural framework within which specialized function may be developed. Three molecules were resolved channel through monomer, thereby defining for permeation. structure complex provides insight into chemical basis selective permeability.