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Structural basis for prodrug recognition by the SLC15 family of proton-coupled peptide transporters

DOI: 10.1073/pnas.1813715116 DOI Help

Authors: Gurdeep S. Minhas (University of Oxford) , Simon Newstead (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Proceedings Of The National Academy Of Sciences , VOL 116 , PAGES 804 - 809

State: Published (Approved)
Published: January 2019
Diamond Proposal Number(s): 18069

Open Access Open Access

Abstract: A major challenge in drug development is the optimization of intestinal absorption and cellular uptake. A successful strategy has been to develop prodrug molecules, which hijack solute carrier (SLC) transporters for active transport into the body. The proton-coupled oligopeptide transporters, PepT1 and PepT2, have been successfully targeted using this approach. Peptide transporters display a remarkable capacity to recognize a diverse library of di- and tripeptides, making them extremely promiscuous and major contributors to the pharmacokinetic profile of several important drug classes, including beta-lactam antibiotics and antiviral and antineoplastic agents. Of particular interest has been their ability to recognize amino acid and peptide-based prodrug molecules, thereby providing a rational approach to improving drug transport into the body. However, the structural basis for prodrug recognition has remained elusive. Here we present crystal structures of a prokaryotic homolog of the mammalian transporters in complex with the antiviral prodrug valacyclovir and the peptide-based photodynamic therapy agent, 5-aminolevulinic acid. The valacyclovir structure reveals that prodrug recognition is mediated through both the amino acid scaffold and the ester bond, which is commonly used to link drug molecules to the carrier’s physiological ligand, whereas 5-aminolevulinic acid makes far fewer interactions compared with physiological peptides. These structures provide a unique insight into how peptide transporters interact with xenobiotic molecules and provide a template for further prodrug development.

Journal Keywords: membrane transport; drug transport; SLC15; proton-coupled transport

Subject Areas: Biology and Bio-materials, Medicine

Instruments: I24-Microfocus Macromolecular Crystallography

Other Facilities: ESRF