Abstract
P2X2 receptors are members of the ATP-gated P2X family of cation channels, and they participate in neurotransmission in sympathetic ganglia and interneurons. Here, we identified 7,7′-(carbonylbis(imino-3,1-phenylenecarbonylimino-3,1-(4-methyl-phenylene)carbonylimino))bis(1-methoxy-naphthalene-3,6-disulfonic acid) tetrasodium salt (NF770) as a nanomolar-potent competitive P2X2 receptor antagonist within a series of 139 suramin derivatives. Three structural determinants contributed to the inhibition of P2X2 receptors by NF770: 1) a “large urea” structure with two symmetric phenylenecarbonylimino groups; 2) attachment of the naphthalene moiety in position 7,7′; and 3) the specific position of two sulfonic acid groups (3,3′; 6,6′) and of one methoxy group (1,1′) at the naphthalene moiety. This structure-activity relationship was interpreted using a rat P2X2 homology model based on the crystal structure of the closed zebrafish P2X4 receptor. Docking of the suramin derivatives into the modeled ATP-binding pocket provides a uniform explanation for the observed differences in inhibitory potencies. Changes in the chemical structure that increase the inhibitory potency of the suramin derivatives improved the spatial orientation within the ATP-binding pocket to allow for stronger polar interactions of functional groups with Gly72, Glu167, or Arg290. Gly72 is responsible for the orientation of the methoxy group close to Arg290 or Glu167. Combined mutational and functional analysis confirmed that residues Gly72 and Glu167 are as important for ATP binding as Arg290, the ATP-binding role of which has been shown in previous studies. The in silico prediction of Gly72 and Glu167 as ATP-binding residues strongly supports the validity of our homology docking.
Footnotes
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The online version of this article (available at http://dmd.aspetjournals.org) contains supplemental material.This work was supported by the Deutsche Forschungsgemeinschaft [Grants Schm 536/8-1/2 (to G.S.), Schm 536/8-2 (to R.H.), Graduiertenkolleg GRK677 (to M.U.K.)].
Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
doi:10.1124/mol.110.068700.
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ABBREVIATIONS:
- A-317491
- 5-[[[(3-Phenoxyphenyl)methyl][(1S)-1,2,3,4-tetrahydro-1-naphthalenyl]amino]carbonyl]-1,2,4-benzenetricarboxylic acid sodium salt hydrate
- RO-3
- 5-(2-isopropyl-4,5-dimethoxy-benzyl)-pyrimidine-2,4-diamine
- RO-4
- 5-(5-iodo-2-isopropyl-4-methoxy-phenoxy)-pyrimidine-2,4-diamine
- GSK314181A
- (adamantan-1-ylmethyl)-5-[(3R-amino-pyrrolidin-1-yl)methyl]-2-chloro-benzamide
- A-740003
- N-(1-{[(cyanoimino)(5-quinolinylamino)methyl]amino}-2,2-dimethylpropyl)-2-(3,4-dimethoxyphenyl)acetamide
- A-804598
- 2-cyano-1-[(1S)-1-phenylethyl]-3-quinolin-5-ylguanidine
- PPADS
- pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid
- TNP-ATP
- 2′,3′-O-(2,4,6-trinitrophenyl)-ATP
- r
- rat
- zf
- zebrafish
- ORi
- oocyte Ringer solution
- αβ-meATP
- αβ-methylene-ATP
- TEVC
- two-electrode voltage-clamp
- PAGE
- polyacrylamide gel electrophoresis
- NF449
- 4,4′,4″,4‴-(carbonylbis(imino-5,1,3-benzenetriyl-bis(carbonylimino)))tetrakisbenzene-1,3-disulfonic acid-octasodium salt
- NF110
- 4,4′,4″,4‴-(carbonylbis(imino-5,1,3-benzenetriyl-bis(carbonylimino)))tetrakisbenzenesulfonic acid
- NF770
- 7,7′-(carbonylbis(imino-3,1-phenylenecarbonylimino-3,1-(4-methyl-phenylene)carbonylimino))bis(1-methoxy-naphthalene-3,6-disulfonic acid) tetrasodium salt
- NF742
- 8,8′-(carbonylbis(imino-3,1-phenylenecarbonylimino-3,1-(4-methyl-phenylene)carbonylimino))bis(1-methoxy-naphthalene-3,6-disulfonic acid) tetrasodium salt
- NF769
- 7,7′-(carbonylbis(imino-3,1-(4-methyl-phenylene)carbonylimino))bis(1-methoxy-naphthalene-3,6-disulfonic acid) tetrasodium salt
- NF778
- 6,6′-(carbonylbis(imino-3,1-phenylenecarbonylimino-3,1-(4-methyl-phenylene)carbonylimino))bis(1-methoxy-naphthalene-3,5-disulfonic acid) tetrasodium salt.
- NF127
- 8,8′-(carbonylbis(imino-3,1-phenylenecarbonylimino-3,1-(4-ethylphenylene)-carbonylimino))bis(naphthalene-1,3,5-trisulfonic acid) hexasodium salt
- NF739
- 8,8′-(carbonylbis(imino-3,1-(4-methylphenylene)carbonylimino))bis(1-methoxynaphthalene-3,6-disulfonic acid) tetrasodium salt
- NF776
- 6,6′-(carbonylbis(imino-3,1-(4-methylphenylene)carbonylimino))bis(1-methoxynaphthalene-3,5-disulfonic acid) tetrasodium salt
- 2D
- two-dimensional
- NF279
- 8,8′-[carbonylbis(imino-4,1-phenylenecarbonylimino-4,1-phenylenecarbonylimino)]bis-1,3,5-naphthalenetrisulfonic acid hexasodium salt
- TM
- transmembrane
- RO-85
- 1-methyl-3-phenyl-1H-thieno[2,3-c]pyrazole-5-carboxylic acid [(R)-2-(4-acetyl-piperazin-1-yl)-1-methyl-ethyl]-amide
- A-839977
- 1-(2,3-dichlorophenyl)-N-[2-(pyridin-2-yloxy)benzyl]-1H-tetrazol-5-amine
- NF708
- 3,3′-(carbonylbis(imino-3,1-phenylene)carbonylimino))bis(benzenephosphonic acid) tetrasodium salt
- NF739
- 8,8′-(carbonylbis(imino-3,1-(4-methylphenylene)carbonylimino))bis(1-methoxynaphthalene-3,6-disulfonic acid)tetrasodium salt.
- Received September 6, 2010.
- Accepted December 29, 2010.
- Copyright © 2011 The American Society for Pharmacology and Experimental Therapeutics
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