HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

NO Electron Donor

Nitric-oxide synthase produces NO from L-arginine.

In animals, nitric oxide (NO) is produced by the nitric-oxide synthases (NOSs). These synthases have flavoprotein domains that provide electrons to a heme in the NOS oxygenase domain, enabling the heme to bind O₂ and synthesize NO. NOS-like proteins have also been found in some prokaryotes. However, the bacterial NOS enzymes lack a flavoprotein domain to reduce their heme and must rely on other proteins for electrons.

In this Paper of the Week, Zhi-Qiang Wang and colleagues tested the ability of two Bacillus subtilis flavodoxins, YkuN and YkuP, to support catalysis by purified B. subtilis NOS (bsNOS). They found that both proteins supported NO synthesis but YkuN was much more efficient at supporting the electron transfer and catalysis by bsNOS. Furthermore, reduced YkuN transferred an electron to the bsNOS ferric heme at rates similar to those measured for heme reduction in the animal NOSs. These results establish YkuN as a kinetically competent redox partner for bsNOS and suggest that flavodoxin proteins may function as physiologic electron donors for NO synthesis in B. subtilis.

FOOTNOTES

See referenced article, J. Biol. Chem. 2007, 282, 2196–2202

[More Papers of the Week]