Abstract
Soluble guanylyl cyclase (sGC) plays an important role in cardiovascular function and catalyzes formation of cGMP. sGC is activated by nitric oxide and allosteric stimulators and activators. However, despite its therapeutic relevance, the regulatory mechanisms of sGC are still incompletely understood. A major reason for this situation is that no crystal structures of active sGC have been resolved so far. An important step toward this goal is the identification of high-affinity ligands that stabilize an sGC conformation resembling the active, “fully closed” state. Therefore, we examined inhibition of rat sGCα1β1 by 38 purine- and pyrimidine-nucleotides with 2,4,6,-trinitrophenyl and (N-methyl)anthraniloyl substitutions at the ribosyl moiety and compared the data with that for the structurally related membranous adenylyl cyclases (mACs) 1, 2, 5 and the purified mAC catalytic subunits VC1:IIC2. TNP-GTP [2′,3′-O-(2,4,6-trinitrophenyl)-GTP] was the most potent sGCα1β1 inhibitor (Ki, 10.7 nM), followed by 2′-MANT-3′-dATP [2′-O-(N-methylanthraniloyl)-3′-deoxy-ATP] (Ki, 16.7 nM). Docking studies on an sGCαcat/sGCβcat model derived from the inactive heterodimeric crystal structure of the catalytic domains point to similar interactions of (M)ANT- and TNP-nucleotides with sGCα1β1 and mAC VC1:IIC2. Reasonable binding modes of 2′-MANT-3′-dATP and bis-(M)ANT-nucleotides at sGC α1β1 require a 3′-endo ribosyl conformation (versus 3′-exo in 3′-MANT-2′-dATP). Overall, inhibitory potencies of nucleotides at sGCα1β1 versus mACs 1, 2, 5 correlated poorly. Collectively, we identified highly potent sGCα1β1 inhibitors that may be useful for future crystallographic and fluorescence spectroscopy studies. Moreover, it may become possible to develop mAC inhibitors with selectivity relative to sGC.
Footnotes
- Received November 26, 2013.
- Accepted January 27, 2014.
This work was supported by the Deutsche Forschungsgemeinschaft (Research Training Group 1910; S.D. and R.S.).
S.D. and K.Y.D. contributed equally to this paper.
Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany, Primary laboratory of origin: Institute of Pharmacology, Hannover Medical School.
- Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics
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