2x79
Inward facing conformation of Mhp1
Structural highlights
FunctionHYUP_MICLQ Nucleobase-proton symporter that mediates the sodium-dependent binding and uptake of 5-aryl-substituted hydantoin compounds (PubMed:16621827, PubMed:24952894). 5-indolyl methyl hydantoin and 5-benzyl hydantoin are the preferred substrates, with selectivity for a hydrophobic substituent in position 5 of hydantoin and for the L isomer over the D isomer (PubMed:16621827, PubMed:24952894).[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe structure of the sodium-benzylhydantoin transport protein Mhp1 from Microbacterium liquefaciens comprises a five-helix inverted repeat, which is widespread among secondary transporters. Here, we report the crystal structure of an inward-facing conformation of Mhp1 at 3.8 angstroms resolution, complementing its previously described structures in outward-facing and occluded states. From analyses of the three structures and molecular dynamics simulations, we propose a mechanism for the transport cycle in Mhp1. Switching from the outward- to the inward-facing state, to effect the inward release of sodium and benzylhydantoin, is primarily achieved by a rigid body movement of transmembrane helices 3, 4, 8, and 9 relative to the rest of the protein. This forms the basis of an alternating access mechanism applicable to many transporters of this emerging superfamily. Molecular basis of alternating access membrane transport by the sodium-hydantoin transporter Mhp1.,Shimamura T, Weyand S, Beckstein O, Rutherford NG, Hadden JM, Sharples D, Sansom MS, Iwata S, Henderson PJ, Cameron AD Science. 2010 Apr 23;328(5977):470-3. PMID:20413494[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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