2X79 : Inward facing conformation of Mhp1

  • Peter J F Henderson (Contributor)
  • Oliver Beckstein (Contributor)
  • David J. Sharples (Contributor)
  • Tatsuro Shimamura (Contributor)
  • Simone Weyand (Contributor)
  • Nicholas G. Rutherford (Contributor)
  • Jonathan M. Hadden (Contributor)
  • David Sharpies (Contributor)
  • Mark S P Sansom (Contributor)
  • So Iwata (Contributor)
  • Alexander D. Cameron (Contributor)



Experimental Technique/Method:X-RAY DIFFRACTION
Release Date:2010-05-05
Deposition Date:2010-02-25
Revision Date:2011-05-08#2011-07-13
Molecular Weight:55556.68
Macromolecule Type:Protein
Residue Count:501
Atom Site Count:3585

The 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.
Date made available2010

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