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Alternating access mechanism in the POT family of oligopeptide transporters

DOI: 10.1038/emboj.2012.157 DOI Help
PMID: 22659829 PMID Help

Authors: Nicolae Solcan (Diamond Light Source) , Jane Kwok (University of Oxford) , Philip W Fowler (University of Oxford, U.K.) , Alexander D Cameron (Diamond Light Source) , David Drew (Imperial College London) , So Iwata (Diamond Light Source) , Simon Newstead (Membrane Protein Laboratory, Imperial College, London)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: The Embo Journal , VOL 31 (16) , PAGES 3411 - 3421

State: Published (Approved)
Published: June 2012
Diamond Proposal Number(s): 7495

Open Access Open Access

Abstract: Short chain peptides are actively transported across membranes as an efficient route for dietary protein absorption and for maintaining cellular homeostasis. In mammals, peptide transport occurs via PepT1 and PepT2, which belong to the proton‐dependent oligopeptide transporter, or POT family. The recent crystal structure of a bacterial POT transporter confirmed that they belong to the major facilitator superfamily of secondary active transporters. Despite the functional characterization of POT family members in bacteria, fungi and mammals, a detailed model for peptide recognition and transport remains unavailable. In this study, we report the 3.3‐Å resolution crystal structure and functional characterization of a POT family transporter from the bacterium Streptococcus thermophilus. Crystallized in an inward open conformation the structure identifies a hinge‐like movement within the C‐terminal half of the transporter that facilitates opening of an intracellular gate controlling access to a central peptide‐binding site. Our associated functional data support a model for peptide transport that highlights the importance of salt bridge interactions in orchestrating alternating access within the POT family.

Journal Keywords: X-Ray; Membrane; Models; Biological; Models; Chemical; Models; Molecular; Protein; Streptococcus thermophilus

Subject Areas: Biology and Bio-materials

Diamond Offline Facilities: Membrane Protein Laboratory (MPL)
Instruments: I02-Macromolecular Crystallography , I03-Macromolecular Crystallography , I04-Macromolecular Crystallography

Added On: 26/09/2012 11:42

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