title: Engineering potent and selective analogues of GpTx-1, a tarantula venom peptide antagonist of the Na(V)1.7 sodium channel.
abstract: NaV1.7 is a voltage-gated sodium ion channel implicated by human genetic evidence as a therapeutic target for the treatment of pain. Screening fractionated venom from the tarantula Grammostola porteri led to the identification of a 34-residue peptide, termed GpTx-1, with potent activity on NaV1.7 (IC50 = 10 nM) and promising selectivity against key NaV subtypes (20× and 1000× over NaV1.4 and NaV1.5, respectively). NMR structural analysis of the chemically synthesized three disulfide peptide was consistent with an inhibitory cystine knot motif. Alanine scanning of GpTx-1 revealed that residues Trp(29), Lys(31), and Phe(34) near the C-terminus are critical for potent NaV1.7 antagonist activity. Substitution of Ala for Phe at position 5 conferred 300-fold selectivity against NaV1.4. A structure-guided campaign afforded additive improvements in potency and NaV subtype selectivity, culminating in the design of [Ala5,Phe6,Leu26,Arg28]GpTx-1 with a NaV1.7 IC50 value of 1.6 nM and >1000× selectivity against NaV1.4 and NaV1.5.
authors: Departments of Therapeutic Discovery, ‡Neuroscience, and §Pharmacokinetics & Drug Metabolism, Amgen Inc. , One Amgen Center Drive, Thousand Oaks, California 91320, United States.
authors: Justin K
authors: JK
authors: Murray
authors: Joseph
authors: J
authors: Ligutti
authors: Dong
authors: D
authors: Liu
authors: Anruo
authors: A
authors: Zou
authors: Leszek
authors: L
authors: Poppe
authors: Hongyan
authors: H
authors: Li
authors: Kristin L
authors: KL
authors: Andrews
authors: Bryan D
authors: BD
authors: Moyer
authors: Stefan I
authors: SI
authors: McDonough
authors: Philippe
authors: P
authors: Favreau
authors: Reto
authors: R
authors: Stöcklin
authors: Les P
authors: LP
authors: Miranda
mesh_terms: D000818:Animals; D004594:Electrophysiology; D005260:Female; D057166:High-Throughput Screening Assays; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D062556:NAV1.7 Voltage-Gated Sodium Channel / Q000097:blood / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology*; D011487:Protein Conformation; D051381:Rats; D021241:Spectrometry, Mass, Electrospray Ionization; D013111:Spider Venoms / Q000737:chemistry / Q000494:pharmacology*; D013112:Spiders; D013329:Structure-Activity Relationship; D061567:Voltage-Gated Sodium Channel Blockers / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D062556:NAV1.7 Voltage-Gated Sodium Channel; D010446:Peptide Fragments; D013111:Spider Venoms; D061567:Voltage-Gated Sodium Channel Blockers