title: Developing Adnectins that target SRC co-activator binding to PXR: a structural approach toward understanding promiscuity of PXR.
abstract: The human pregnane X receptor (PXR) is a promiscuous nuclear receptor that functions as a sensor to a wide variety of xenobiotics and regulates expression of several drug metabolizing enzymes and transporters. We have generated "Adnectins", derived from 10th fibronectin type III domain ((10)Fn3), that target the PXR ligand binding domain (LBD) interactions with the steroid receptor co-activator-1 (SRC-1) peptide, displacing SRC-1 binding. Adnectins are structurally homologous to the immunoglobulin superfamily. Three different co-crystal structures of PXR LBD with Adnectin-1 and CCR1 (CC chemokine receptor-1) antagonist Compound-1 were determined. This structural information was used to modulate PXR affinity for a related CCR1 antagonist compound that entered into clinical trials for rheumatoid arthritis. The structures of PXR with Adnectin-1 reveal specificity of Adnectin-1 in not only targeting the interface of the SRC-1 interactions but also engaging the same set of residues that are involved in binding of SRC-1 to PXR. Substituting SRC-1 with Adnectin-1 does not alter the binding conformation of Compound-1 in the ligand binding pocket. The structure also reveals the possibility of using Adnectins as crystallization chaperones to generate structures of PXR with compounds of interest.
authors.affiliation: Bristol-Myers Squibb Research and Development, PO Box 4000, Princeton, NJ 08543-4000, USA. Electronic address: javed.khan@bms.com.
authors.forename: Javed A
authors.initials: JA
authors.lastname: Khan
authors.affiliation: Bristol-Myers Squibb Research and Development, PO Box 4000, Princeton, NJ 08543-4000, USA.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Camac
authors.affiliation: Adnexus, 100 Beaver Street, Waltham, MA 02453, USA.
authors.forename: Simon
authors.initials: S
authors.lastname: Low
authors.affiliation: Bristol-Myers Squibb Research and Development, PO Box 4000, Princeton, NJ 08543-4000, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Tebben
authors.affiliation: Adnexus, 100 Beaver Street, Waltham, MA 02453, USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Wensel
authors.affiliation: Adnexus, 100 Beaver Street, Waltham, MA 02453, USA.
authors.forename: Martin C
authors.initials: MC
authors.lastname: Wright
authors.affiliation: Adnexus, 100 Beaver Street, Waltham, MA 02453, USA.
authors.forename: Julie
authors.initials: J
authors.lastname: Su
authors.affiliation: Adnexus, 100 Beaver Street, Waltham, MA 02453, USA.
authors.forename: Victoria
authors.initials: V
authors.lastname: Jenny
authors.affiliation: Adnexus, 100 Beaver Street, Waltham, MA 02453, USA.
authors.forename: Ruchira Das
authors.initials: RD
authors.lastname: Gupta
authors.affiliation: Bristol-Myers Squibb Research and Development, PO Box 4000, Princeton, NJ 08543-4000, USA.
authors.forename: Max
authors.initials: M
authors.lastname: Ruzanov
authors.affiliation: Adnexus, 100 Beaver Street, Waltham, MA 02453, USA.
authors.forename: Katie A
authors.initials: KA
authors.lastname: Russo
authors.affiliation: Bristol-Myers Squibb Research and Development, PO Box 4000, Princeton, NJ 08543-4000, USA.
authors.forename: Aneka
authors.initials: A
authors.lastname: Bell
authors.affiliation: Bristol-Myers Squibb Research and Development, PO Box 4000, Princeton, NJ 08543-4000, USA.
authors.forename: Yongmi
authors.initials: Y
authors.lastname: An
authors.affiliation: Bristol-Myers Squibb Research and Development, PO Box 4000, Princeton, NJ 08543-4000, USA.
authors.forename: James W
authors.initials: JW
authors.lastname: Bryson
authors.affiliation: Bristol-Myers Squibb Research and Development, PO Box 4000, Princeton, NJ 08543-4000, USA.
authors.forename: Mian
authors.initials: M
authors.lastname: Gao
authors.affiliation: Adnexus, 100 Beaver Street, Waltham, MA 02453, USA.
authors.forename: Pallavi
authors.initials: P
authors.lastname: Gambhire
authors.affiliation: Bristol-Myers Squibb Research and Development, PO Box 4000, Princeton, NJ 08543-4000, USA.
authors.forename: Eric T
authors.initials: ET
authors.lastname: Baldwin
authors.affiliation: Bristol-Myers Squibb Research and Development, PO Box 4000, Princeton, NJ 08543-4000, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Gardner
authors.affiliation: Bristol-Myers Squibb Research and Development, PO Box 4000, Princeton, NJ 08543-4000, USA.
authors.forename: Cullen L
authors.initials: CL
authors.lastname: Cavallaro
authors.affiliation: Bristol-Myers Squibb Research and Development, PO Box 4000, Princeton, NJ 08543-4000, USA.
authors.forename: John V
authors.initials: JV
authors.lastname: Duncia
authors.affiliation: Bristol-Myers Squibb Research and Development, PO Box 4000, Princeton, NJ 08543-4000, USA.
authors.forename: John
authors.initials: J
authors.lastname: Hynes
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D006801:Humans; D017705:Lignans / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D056920:Nuclear Receptor Coactivator 1 / Q000737:chemistry*; D000077297:Pregnane X Receptor; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D054389:Receptors, CCR1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011987:Receptors, Steroid / Q000737:chemistry*; D016415:Sequence Alignment; D020349:Surface Plasmon Resonance; D014508:Urea / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D014633:Valine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology
chemical_list: C000593258:1-(1-(4-(4-chlorophenyl)-4-hydroxy-3,3-dimethylpiperidin-1-yl)-3-methyl-1-oxobutan-2-yl)-3-(2-hydroxy-2-methylpropyl)urea; C515300:CCR1 protein, human; D017705:Lignans; D000077297:Pregnane X Receptor; D054389:Receptors, CCR1; D011987:Receptors, Steroid; D014508:Urea; C538859:NCOA1 protein, human; D056920:Nuclear Receptor Coactivator 1; D014633:Valine
keywords: Adnectin; CCR1; PXR; SRC-1; nuclear receptor