4D1B

STRUCTURE OF MHP1, A NUCLEOBASE-CATION-SYMPORT-1 FAMILY TRANSPORTER, IN A CLOSED CONFORMATION WITH BENZYL-HYDANTOIN

Replaces:  2JLO

Summary for 4D1B

• Entry DOI: 10.2210/pdb4d1b/pdb
• Related: 4D1A 4D1C 4D1D
• Descriptor: HYDANTOIN TRANSPORT PROTEIN, (5S)-5-benzylimidazolidine-2,4-dione, SODIUM ION (3 entities in total)
• Functional Keywords: transport protein, membrane protein transporter, substrate-bound, occluded state
• Biological source: MICROBACTERIUM LIQUEFACIENS
• Total number of polymer chains: 1
• Total formula weight: 54230.34

Authors

Brueckner, F.,Geng, T.,Weyand, S.,Drew, D.,Iwata, S.,Henderson, P.J.F.,Cameron, A.D. (deposition date: 2014-05-01, release date: 2014-07-02, Last modification date: 2023-12-20)

Primary citation

Simmons, K.J.,Jackson, S.M.,Brueckner, F.,Patching, S.G.,Beckstein, O.,Ivanova, E.,Geng, T.,Weyand, S.,Drew, D.,Lanigan, J.,Sharples, D.J.,Sansom, M.S.,Iwata, S.,Fishwick, C.W.,Johnson, A.P.,Cameron, A.D.,Henderson, P.J.
Molecular Mechanism of Ligand Recognition by Membrane Transport Protein, Mhp1.
Embo J., 33:1831-, 2014

PubMed Abstract: The hydantoin transporter Mhp1 is a sodium-coupled secondary active transport protein of the nucleobase-cation-symport family and a member of the widespread 5-helix inverted repeat superfamily of transporters. The structure of Mhp1 was previously solved in three different conformations providing insight into the molecular basis of the alternating access mechanism. Here, we elucidate detailed events of substrate binding, through a combination of crystallography, molecular dynamics, site-directed mutagenesis, biochemical/biophysical assays, and the design and synthesis of novel ligands. We show precisely where 5-substituted hydantoin substrates bind in an extended configuration at the interface of the bundle and hash domains. They are recognised through hydrogen bonds to the hydantoin moiety and the complementarity of the 5-substituent for a hydrophobic pocket in the protein. Furthermore, we describe a novel structure of an intermediate state of the protein with the external thin gate locked open by an inhibitor, 5-(2-naphthylmethyl)-L-hydantoin, which becomes a substrate when leucine 363 is changed to an alanine. We deduce the molecular events that underlie acquisition and transport of a ligand by Mhp1.

PubMed: 24952894
DOI: 10.15252/EMBJ.201387557

Experimental method

X-RAY DIFFRACTION (3.8 Å)