Glycoside-pentoside-hexuronide:cation symporter family
| Identifiers | |
|---|---|
| Symbol | ? |
| InterPro | IPR001927 |
| TCDB | 2.A.2 |
| OPM superfamily | 15 |
| OPM protein | 4m64 |
The Glycoside-Pentoside-Hexuronide (GPH):Cation Symporter Family is part of the major facilitator superfamily and catalyzes uptake of sugars (mostly, but not exclusively, glycosides) in symport with a monovalent cation (H+ or Na+).[1] The various members of the family have been reported to use Na+, H+ or Li, Na+ or Li+, or all three cations as the symported cation.
Structure[edit]
Proteins of the GHP family are generally about 500 amino acids in length, although the Gram-positive bacterial lactose permeases are larger, due to a C-terminal hydrophilic domain that is involved in regulation by the phosphotransferase system. All of these proteins possess twelve putative transmembrane α-helical spanners.
Homology[edit]
Homologues are from bacteria, including the distantly related sucrose:H+ symporters of plants and a yeast maltose/sucrose:H+ symporter of Schizosaccharomyces pombe. This yeast protein is about 24% identical to the plant sucrose:H+ symporters and is more distantly related to the bacterial members of the GPH family.[2] Limited sequence similarity of some of these proteins with members of the major facilitator superfamily has been observed, and their 3D structures are clearly similar.
Transport Reaction[edit]
The generalized transport reaction catalyzed by the GPH:cation symporter family is:
- Sugar (out) + [H+ or Na+] (out) → Sugar (in) + [H+ or Na+] (in)
References[edit]
- ^ Heuberger EH, Smits E, Poolman B (September 2001). "Xyloside transport by XylP, a member of the galactoside-pentoside-hexuronide family". The Journal of Biological Chemistry. 276 (37): 34465–72. doi:10.1074/jbc.M105460200. PMID 11408491.
- ^ Reinders A, Ward JM (January 2001). "Functional characterization of the alpha-glucoside transporter Sut1p from Schizosaccharomyces pombe, the first fungal homologue of plant sucrose transporters". Molecular Microbiology. 39 (2): 445–54. doi:10.1046/j.1365-2958.2001.02237.x. PMID 11136464. S2CID 5743600.
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