title: Crystal structure of the aquaglyceroporin PfAQP from the malarial parasite Plasmodium falciparum.
abstract: The 2.05-A resolution structure of the aquaglyceroporin from the malarial parasite Plasmodium falciparum (PfAQP), a protein important in the parasite's life cycle, has been solved. The structure provides key evidence for the basis of water versus glycerol selectivity in aquaporin family members. Unlike its closest homolog of known structure, GlpF, the channel conducts both glycerol and water at high rates, framing the question of what determines high water conductance in aquaporin channels. The universally conserved arginine in the selectivity filter is constrained by only two hydrogen bonds in GlpF, whereas there are three in all water-selective aquaporins and in PfAQP. The decreased cost of dehydrating the triply-satisfied arginine cation may provide the basis for high water conductance. The two Asn-Pro-Ala (NPA) regions of PfAQP, which bear rare substitutions to Asn-Leu-Ala (NLA) and Asn-Pro-Ser (NPS), participate in preserving the orientation of the selectivity filter asparagines in the center of the channel.
authors.affiliation: Department of Chemistry, Genentech Hall, School of Medicine, University of California in San Francisco, 600 16th Street, San Francisco, California 94158-2517, USA.
authors.forename: Zachary E R
authors.initials: ZE
authors.lastname: Newby
authors.forename: Joseph
authors.initials: J
authors.lastname: O'Connell
authors.forename: Yaneth
authors.initials: Y
authors.lastname: Robles-Colmenares
authors.forename: Shahram
authors.initials: S
authors.lastname: Khademi
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Miercke
authors.forename: Robert M
authors.initials: RM
authors.lastname: Stroud
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D051397:Aquaglyceroporins / Q000737:chemistry*; D001120:Arginine; D018360:Crystallography, X-Ray; D010963:Plasmodium falciparum / Q000737:chemistry*; D018272:Porins / Q000737:chemistry*; D011487:Protein Conformation; D015800:Protozoan Proteins / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D051397:Aquaglyceroporins; C449801:PfAQP protein, Plasmodium falciparum; D018272:Porins; D015800:Protozoan Proteins; D014867:Water; D001120:Arginine