PDBsum entry 4d1b

Transport protein

PDB id: 4d1b

Contents

Protein chain

456 a.a.

Ligands

5FH

Metals

_NA

PDB id:

4d1b

Name:

Transport protein

Title:

Structure of mhp1, a nucleobase-cation-symport-1 family transporter, in a closed conformation with benzyl-hydantoin

Structure:

Hydantoin transport protein. Chain: a. Fragment: residues 1-487. Synonym: mhp1. Engineered: yes

Source:

Microbacterium liquefaciens. Organism_taxid: 33918. Strain: aj3912. Expressed in: escherichia coli. Expression_system_taxid: 469008. Expression_system_variant: lemo21.

Resolution:

3.80Å R-factor: 0.286 R-free: 0.308

Authors:

F.Brueckner,T.Geng,S.Weyand,D.Drew,S.Iwata,P.J.F.Henderson, A.D.Cameron

Key ref:

K.J.Simmons et al. (2014). Molecular mechanism of ligand recognition by membrane transport protein, Mhp1. Embo J, 33, 1831-1844. PubMed id: 24952894 DOI: 10.15252/embj.201387557

Date:

01-May-14 Release date: 02-Jul-14

Supersedes:

2jlo

Protein chain

D6R8X8  (HYUP_MICLQ) -  Hydantoin permease from Microbacterium liquefaciens

Seq: 489 a.a.

Struc: 456 a.a.

DOI no: 10.15252/embj.201387557

Embo J 33:1831-1844 (2014)

PubMed id: 24952894

Molecular mechanism of ligand recognition by membrane transport protein, Mhp1.

K.J.Simmons, S.M.Jackson, F.Brueckner, S.G.Patching, O.Beckstein, E.Ivanova, T.Geng, S.Weyand, D.Drew, J.Lanigan, D.J.Sharples, M.S.Sansom, S.Iwata, C.W.Fishwick, A.P.Johnson, A.D.Cameron, P.J.Henderson.

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.