Long W , Panigrahi R , Panwar P , Wong K , O Neill D , Chen XZ , Lemieux MJ , Cheeseman CI .

	Figure 1. List of residues involved in interaction with urate in SLC2A9 and fructose in SLC2A9/SLC2A5.Note: The residues of SLC2A9 and SLC2A5 located at the similar position are color coded. The transmembrane helices to which the residues belong have been noted.
	Figure 2. Docking studies of human SLC2A9b with fructose and urate.Panel (A and B) Binding pocket for fructose and urate, respectively. The residues involved in hydrogen bonding interaction (orange dash lines) have been shown in stick (green). The nitrogen and oxygen atoms are shown in blue and red respectively. The nitrogen and oxygen atoms are shown in blue and red respectively. Panel (C and D) Ligplot showing all the residues forming the binding pocket for fructose and urate, respectively. Hydrogen bonding interactions are shown in green dashed lines and the hydrophobically interacting pairs of atom are shown in red lines patterns.
	Figure 3. Urate and fructose transport mediated by WT hSLC2A9 and its Y298Q and N429H mutants.Panel (A) Michaelis-Menten curves of 14C urate kinetics of hSLC2A9 WT (▪), Y298Q (○) and N429H (Δ). Panel (B) 14C urate kinetic constants and the standard error of the regression (Sy. X) of the three isoforms (n ≥ 3). Panel (C) Michaelis-Menten curves of urate-induced currents of WT hSLC2A9, Y298Q and N429H mutants. Panel (D) Urate-induced current kinetic constants and the standard error of the regression (Sy. X) of the WT and two mutants (n ≥ 15 oocytes from 3 frogs). Panel (E) Current-voltage curve of 1 mM urate-induced current obtained using a RAMP protocol WT hSLC2A9 (▪), Y298Q (○) and N429H (Δ) mutant expressing oocytes. (n ≥ 15 oocytes from 3 frogs). Panel (F) 14C fructose uptake mediated by WT hSLC2A9 and its mutants. (n ≥ 3, One-way ANOVA, *p < 0.05).
	Figure 4. Urate and fructose transport mediated by WT hSLC2A9 and its cysteine mutants.Panel (A) Molecular model of human SLC2A9b with predicted locations of cysteine residues. View from the extracellular side of the outward facing conformation of hSLC2A9b. Panel (B) 14C fructose uptake mediated by WT hSLC2A9 and its cysteine mutants. Bar graphs represent fructose uptake activities, which were corrected for non-specific transport measured in control water injected oocytes from the same batch of oocytes (n ≥ 3, One-way ANOVA, *p < 0.05). Panel (C) Michaelis-Menten curves of 14C urate kinetics of hSLC2A9 WT (◼) and its mutants C297G (⬒), C451S (⬓), C181T (♢), C398A (▴), double mutant C181T/C398A (▿), C301S (), and C459L ().Uptake activity was corrected for non-specific transport measured in control water injected oocytes from the same batch of oocytes. Panel (D) Michaelis-Menten curves of urate-induced currents of WT hSLC2A9 and its cysteine mutants. Panel (E) 14C urate kinetic constants of the 3 isoforms (n ≥ 3). Panel (F) Urate-induced current kinetic constants of the WT and cysteine mutants (n ≥ 15 oocytes from 3 frogs).
	Figure 5. Urate and fructose transport mediated by WT hSLC2A9 and its C128V mutant.Panel (A) Michaelis-Menten curves of 14C urate kinetics of hSLC2A9b WT (◼) and C128V (◻).Panel (B) 14C urate kinetic constants and the standard error of the regression (Sy. X) of the 2 isoforms (n = 3). Panel (C) Michaelis-Menten curves of urate-induced currents of WT hSLC2A9b WT and C128V mutant. Panel (D) Urate-induced current kinetic constants and the standard error of the regression (Sy. X) of the WT and C128V mutant (n = 15 oocytes from 3 frogs). Panel (E) Representative pictures of immunohistochemistry and Western blot analysis of protein expression of C128V mutant expressing oocytes. Panel (F) 14C fructose uptake mediated by hSLC2A9b WT and C128V mutant (n = 3).
	Figure 6. pCMBS inhibition experiments.Panel (A) pCMBS screening in 14C urate uptake mediated by WT hSLC2A9 and its cysteine mutants. Bar graphs represent 100 μM urate uptake activities before (dark) and after (white) 100 μM pCMBS treatments. Data was corrected for non-specific transport measured in control water injected oocytes from the same batch of oocytes (n ≥ 3, unpaired t-test, *p < 0.05). Panel (B) pCMBS inhibition curves of urate-induced currents of WT hSLC2A9 (◼) expressing and control water injected (○) oocytes (n ≥ 15 oocytes from 3 frogs). Panel (C) pCMBS inhibition curves of urate-induced current of WT hSLC2A9 (◼) and C181T (◊) protein expressing oocytes. Data were corrected with basal currents before the pCMBS treatment. IC50 is the pCMBS concentration for 50% inhibition of the urate-induced current (n ≥ 15 oocytes from 3 frogs). Panel (D and E) Representative trace of urate protecting pCMBS inhibition and control experiment, respectively. Urate-induced current was elicited by perfusing an oocyte expression WT hSLC2A9 (upper trace) or water injected oocyte (lower trace) with 1 mM urate (first urate-induced peak) followed by 1 min 100 μM pCMBS incubation. The oocyte then was washed with STM for at least 1 min to remove both extracellular pCMBS and urate. Finally, the oocyte was perfused with 1 mM urate again (second urate-induced peak). Panel (F) Urate protecting pCMBS inhibition experiments of WT hSLC2A9 and C181T. Bar graphs are data corrected to control (first peak of urate-induced current before pCMBS treatment) currents (dark) currents after oocyte in both 1 mM urate and 100 μM pCMBS (grey), and currents after oocyte in only 100 μM pCMBS (white) (n ≥ 15 oocytes from 3 frogs, One-way ANOVA, *p < 0.05).
	Figure 7. Fructose and urate transport mediated by WT hSLC2A9, its chimæra hSLC2A9(7)5 and hSLC2A9(7)5 G297C/S301C.Panel (A) 14C fructose uptake mediated by WT hSLC2A9 and its chimæric mutants. (n ≥ 3, One-way ANOVA, *p < 0.05). Panel (B) Michaelis-Menten curves of 14C urate kinetics of hSLC2A9 WT (◼), its chimærichSLC2A9(7)5 (◻), and hSLC2A9(7)5 G297C/S301C (▴). Panel (C) 14C urate kinetic constants and the standard error of the regression (Sy. X) of the 3 isoforms (n ≥ 3). Panel (D) Michaelis-Menten curves of urate-induced currents of WT hSLC2A9 and its chimæric mutants. Currents were measured by TEVC. Panel E. Urate-induced current kinetic constants and the standard error of the regression (Sy. X) of the WT and its chimæric mutants (n ≥ 15 oocytes from 3 frogs).
	Figure 8. Fructose and urate transport mediated by WT hSLC2A5, its chimæra hSLC2A5(7)9 and hSLC2A5(7)9 T171C/A388C/S441C.Panel (A) 14C fructose uptake mediated by WT hSLC2A5 and its chimæric mutants. (n ≥ 3, One-way ANOVA, *p < 0.05). Panel (B) 14C urate uptake time course experiment of hSLC2A9, WT (◼), WT hSLC2A5 (⚪), hSLC2A5(7)9 (▵) and hSLC2A5(7)9 T171C/A388C/S441C (▴).

Abramson, Structure and mechanism of the lactose permease of Escherichia coli. 2003, Pubmed

Abramson, Structure and mechanism of the lactose permease of Escherichia coli. 2003, Pubmed
Bibee, Asymmetric syncytial expression of GLUT9 splice variants in human term placenta and alterations in diabetic pregnancies. 2011, Pubmed
Bieganski, Novel ligands that target the mitochondrial membrane protein mitoNEET. 2011, Pubmed
Carruthers, Facilitated diffusion of glucose. 1990, Pubmed
Caulfield, SLC2A9 is a high-capacity urate transporter in humans. 2008, Pubmed , Xenbase
Clémençon, Expression, purification, and structural insights for the human uric acid transporter, GLUT9, using the Xenopus laevis oocytes system. 2014, Pubmed , Xenbase
Craik, Protein folding: Turbo-charged crosslinking. 2012, Pubmed
Cunningham, Reptation-induced coalescence of tunnels and cavities in Escherichia Coli XylE transporter conformers accounts for facilitated diffusion. 2014, Pubmed
Dang, Structure of a fucose transporter in an outward-open conformation. 2010, Pubmed
Deng, Crystal structure of the human glucose transporter GLUT1. 2014, Pubmed
Hebert, Glucose transporter oligomeric structure determines transporter function. Reversible redox-dependent interconversions of tetrameric and dimeric GLUT1. 1992, Pubmed
Hetényi, Blind docking of drug-sized compounds to proteins with up to a thousand residues. 2006, Pubmed
Hruz, Structural analysis of the GLUT1 facilitative glucose transporter (review). 2001, Pubmed
Hruz, Cysteine-scanning mutagenesis of transmembrane segment 7 of the GLUT1 glucose transporter. 1999, Pubmed , Xenbase
Kayano, Human facilitative glucose transporters. Isolation, functional characterization, and gene localization of cDNAs encoding an isoform (GLUT5) expressed in small intestine, kidney, muscle, and adipose tissue and an unusual glucose transporter pseudogene-like sequence (GLUT6). 1990, Pubmed , Xenbase
Li, FastCloning: a highly simplified, purification-free, sequence- and ligation-independent PCR cloning method. 2011, Pubmed , Xenbase
Long, Critical Roles of Two Hydrophobic Residues within Human Glucose Transporter 9 (hSLC2A9) in Substrate Selectivity and Urate Transport. 2015, Pubmed , Xenbase
Manolescu, A highly conserved hydrophobic motif in the exofacial vestibule of fructose transporting SLC2A proteins acts as a critical determinant of their substrate selectivity. 2007, Pubmed , Xenbase
Manolescu, Identification of a hydrophobic residue as a key determinant of fructose transport by the facilitative hexose transporter SLC2A7 (GLUT7). 2005, Pubmed , Xenbase
Mueckler, Model of the exofacial substrate-binding site and helical folding of the human Glut1 glucose transporter based on scanning mutagenesis. 2009, Pubmed , Xenbase
Mueckler, Cysteine-scanning mutagenesis and substituted cysteine accessibility analysis of transmembrane segment 4 of the Glut1 glucose transporter. 2005, Pubmed , Xenbase
Nomura, Structure and mechanism of the mammalian fructose transporter GLUT5. 2015, Pubmed
Pallaghy, A common structural motif incorporating a cystine knot and a triple-stranded beta-sheet in toxic and inhibitory polypeptides. 1994, Pubmed
Park, Cysteine residues in the transmembrane (TM) 9 to TM11 region of the human equilibrative nucleoside transporter subtype 1 play an important role in inhibitor binding and translocation function. 2012, Pubmed
Roy, I-TASSER: a unified platform for automated protein structure and function prediction. 2010, Pubmed
Roy, A protocol for computer-based protein structure and function prediction. 2011, Pubmed
Silverman, Structure and function of hexose transporters. 1991, Pubmed
Sun, Crystal structure of a bacterial homologue of glucose transporters GLUT1-4. 2012, Pubmed
Thornton, Disulphide bridges in globular proteins. 1981, Pubmed
Trott, AutoDock Vina: improving the speed and accuracy of docking with a new scoring function, efficient optimization, and multithreading. 2010, Pubmed
Vaziri, Use of molecular modelling to probe the mechanism of the nucleoside transporter NupG. 2013, Pubmed
Vitart, SLC2A9 is a newly identified urate transporter influencing serum urate concentration, urate excretion and gout. 2008, Pubmed , Xenbase
Walmsley, The dynamics of the glucose transporter. 1988, Pubmed
Wang, Automatic atom type and bond type perception in molecular mechanical calculations. 2006, Pubmed
Wellner, From triple cysteine mutants to the cysteine-less glucose transporter GLUT1: a functional analysis. 1995, Pubmed , Xenbase
Witkowska, Human SLC2A9a and SLC2A9b isoforms mediate electrogenic transport of urate with different characteristics in the presence of hexoses. 2012, Pubmed , Xenbase
Yao, Identification of Cys140 in helix 4 as an exofacial cysteine residue within the substrate-translocation channel of rat equilibrative nitrobenzylthioinosine (NBMPR)-insensitive nucleoside transporter rENT2. 2001, Pubmed , Xenbase
Zottola, Glucose transporter function is controlled by transporter oligomeric structure. A single, intramolecular disulfide promotes GLUT1 tetramerization. 1995, Pubmed