Characterization of nitrosoalkane binding and activation of soluble guanylate cyclase

Biochemistry. 2005 Dec 13;44(49):16257-65. doi: 10.1021/bi0515671.


Soluble guanylate cyclase (sGC) is the primary receptor for the signaling agent nitric oxide (NO). Electronic absorption and resonance Raman spectroscopy were used to show that nitrosoalkanes bind to the heme of sGC to form six-coordinate, low-spin complexes. In the sGC-nitrosopentane complex, a band assigned to an Fe-N stretching vibration is observed at 543 cm(-)(1) which is similar to values reported for other six-coordinate NO-bound hemoproteins. Nitrosoalkanes activate sGC 2-6-fold and synergize with YC-1, a synthetic benzylindazole derivative, to activate the enzyme 11-47-fold. In addition, the observed off-rates of nitrosoalkanes from sGC were found to be dependent on the alkyl chain length. A linear correlation was found between the observed off-rates and the alkyl chain length which suggests that the sGC heme has a large hydrophobic distal ligand-binding pocket. Together, these data show that nitrosoalkanes are a novel class of heme-based sGC activators and suggest that heme ligation is a general requirement for YC-1 synergism.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alkanes / chemistry
  • Alkanes / metabolism*
  • Animals
  • Enzyme Activation
  • Guanylate Cyclase / chemistry
  • Guanylate Cyclase / genetics
  • Guanylate Cyclase / metabolism*
  • Nitric Oxide / metabolism
  • Nitroso Compounds / chemistry
  • Nitroso Compounds / metabolism*
  • Protein Binding
  • Spectrum Analysis, Raman


  • Alkanes
  • Nitroso Compounds
  • Nitric Oxide
  • Guanylate Cyclase