Format

Send to

Choose Destination
J Biol Chem. 2017 Jan 13;292(2):446-461. doi: 10.1074/jbc.M116.755884. Epub 2016 Nov 18.

Structures of the Multidrug Transporter P-glycoprotein Reveal Asymmetric ATP Binding and the Mechanism of Polyspecificity.

Author information

1
From the Laboratory of Cell Biology, Center for Cancer Research, NCI.
2
the Biotechnology Unit, NIDDK, and.
3
the Vaccine Research Center, NIAID, National Institutes of Health, Bethesda, Maryland 20892.
4
From the Laboratory of Cell Biology, Center for Cancer Research, NCI, xiad@mail.nih.gov.

Abstract

P-glycoprotein (P-gp) is a polyspecific ATP-dependent transporter linked to multidrug resistance in cancer; it plays important roles in determining the pharmacokinetics of many drugs. Understanding the structural basis of P-gp, substrate polyspecificity has been hampered by its intrinsic flexibility, which is facilitated by a 75-residue linker that connects the two halves of P-gp. Here we constructed a mutant murine P-gp with a shortened linker to facilitate structural determination. Despite dramatic reduction in rhodamine 123 and calcein-AM transport, the linker-shortened mutant P-gp possesses basal ATPase activity and binds ATP only in its N-terminal nucleotide-binding domain. Nine independently determined structures of wild type, the linker mutant, and a methylated P-gp at up to 3.3 Å resolution display significant movements of individual transmembrane domain helices, which correlated with the opening and closing motion of the two halves of P-gp. The open-and-close motion alters the surface topology of P-gp within the drug-binding pocket, providing a mechanistic explanation for the polyspecificity of P-gp in substrate interactions.

KEYWORDS:

ABC transporter; ATP-binding; ATPase; P-glycoprotein; asymmetry; crystal structure; glycoprotein; multidrug transporter; polyspecificity; structure

PMID:
27864369
PMCID:
PMC5241723
DOI:
10.1074/jbc.M116.755884
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center