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

The Journal of biological chemistry 2017 Jan 13

filter terms:

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. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Citation

Lothar Esser, Fei Zhou, Kristen M Pluchino, Joseph Shiloach, Jichun Ma, Wai-Kwan Tang, Camilo Gutierrez, Alex Zhang, Suneet Shukla, James P Madigan, Tongqing Zhou, Peter D Kwong, Suresh V Ambudkar, Michael M Gottesman, Di Xia. Structures of the Multidrug Transporter P-glycoprotein Reveal Asymmetric ATP Binding and the Mechanism of Polyspecificity. The Journal of biological chemistry. 2017 Jan 13;292(2):446-461