title: Structural analysis of CXCR4 - Antagonist interactions using saturation-transfer double-difference NMR.
abstract: CXCR4 is a GPCR involved in leukocyte trafficking. Small molecule antagonists of the receptor may treat inflammatory disease, cancer and HIV. Here we probe the binding of a tetrahydroisoquinoline-based antagonist (TIQ-10) to CXCR4 using saturation transfer double-difference (STDD) NMR. STDD spectra were acquired using extracts from Chinese Hamster Ovary cells expressing membrane-embedded CXCR4. The experiments demonstrate competitive binding between TIQ-10 and established antagonists and provide the TIQ-10 - CXCR4 binding epitope. Molecular modeling of TIQ-10 into the binding pocket provides a pose consistent with STDD-derived interactions. This study paves the way for future investigations of GPCR-ligand interactions in a biological milieu for use in chemical biology, biochemistry, structural biology, and rational drug design.
authors: Emory University, Department of Chemistry, 1515 Dickey Dr., Atlanta, GA 30322, USA.
authors: Bryan D
authors: BD
authors: Cox
authors: Emory University, Department of Chemistry, 1515 Dickey Dr., Atlanta, GA 30322, USA.
authors: Anil K
authors: AK
authors: Mehta
authors: Emory University, Department of Chemistry, 1515 Dickey Dr., Atlanta, GA 30322, USA.
authors: John O
authors: JO
authors: DiRaddo
authors: Emory University, Department of Chemistry, 1515 Dickey Dr., Atlanta, GA 30322, USA.
authors: Dennis C
authors: DC
authors: Liotta
authors: Emory University, Department of Chemistry, 1515 Dickey Dr., Atlanta, GA 30322, USA.
authors: Lawrence J
authors: LJ
authors: Wilson
authors: Emory University, Department of Chemistry, 1515 Dickey Dr., Atlanta, GA 30322, USA. Electronic address: jsnyder@emory.edu.
authors: James P
authors: JP
authors: Snyder
mesh_terms: D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D006801:Humans; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D019718:Receptors, CXCR4 / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism*; D044005:Tetrahydroisoquinolines / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: C527276:CXCR4 protein, human; D019718:Receptors, CXCR4; D044005:Tetrahydroisoquinolines
keywords: C-X-C chemokine receptor 4; G-protein-coupled receptors; Ligand–receptor interactions; NMR spectroscopy; Saturation transfer difference