NMR STRUCTURE AND ACTION ON NICOTINIC ACETYLCHOLINE RECEPTORS OF WATER-SOLUBLE DOMAIN OF HUMAN LYNX1.
NMR STRUCTURE AND ACTION ON NICOTINIC ACETYLCHOLINE RECEPTORS OF WATER-SOLUBLE DOMAIN OF HUMAN LYNX1.
J Biol Chem. 2011 Jan 20;
Authors: Lyukmanova EN, Shenkarev ZO, Shulepko MA, Mineev KS, D'Hoedt D, Kasheverov IE, Filkin SY, Krivolapova AP, Janickova H, Dolezal V, Dolgikh DA, Arseniev AS, Bertrand D, Tsetlin VI, Kirpichnikov MP
Discovery of proteins expressed in the central nervous system sharing the three-finger structure with snake ?-neurotoxins provoked much interest to their role in brain functions. Prototoxin lynx1, having homology both to Ly6 proteins and three-finger neurotoxins, is the first identified member of this family membrane-tethered by a GPI anchor, which considerably complicates in vitro studies. We report for the first time the NMR spatial structure for the water-soluble domain of human lynx1 lacking a GPI anchor (ws-lynx1) and its concentration-dependent activity on nicotinic acetylcholine receptors (nAChRs). At 5-30 ?M ws-lynx1 competed with 125I-?-bungarotoxin for binding to the acetylcholine-binding proteins (AChBPs) and to Torpedo nAChR. Exposure of Xenopus oocytes expressing ?7 nAChRs to 1 ?M ws-lynx1 enhanced the response to acetylcholine but no effect was detected on ?4?2 and ?3?2 nAChRs. Increasing ws-lynx1 concentration to 10 ?M caused a modest inhibition of these three nAChR subtypes. A common feature for ws-lynx1 and lynx1 is a decrease of nAChR sensitivity to high concentrations of acetylcholine. NMR and functional analysis both demonstrate that ws-lynx1 is an appropriate model to shed light on the mechanism of lynx1 action. Computer modeling, based on ws-lynx1 NMR structure and AChBP X-ray structure, revealed a possible mode of ws-lynx1 binding.
PMID: 21252236 [PubMed - as supplied by publisher]
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PubMed