NMR spectroscopic studies of the hydrogenosomal [2Fe-2S] ferredoxin from Trichomonas vaginalis: Hyperfine-shifted H-1 resonances

The hyperfine-shifted H-1 NMR resonances of oxidized and reduced Trichomona s vaginalis ferredoxin, a functionally unique [2Fe-2S] ferredoxin, have bee n studied. The oxidized protein spectrum displayed a pattern of six broad u pfield-shifted resonances between 13 and 40 ppm with chemical shifts distin ct from those of other [2Fe-2S] ferredoxins. All hyperfine H-1 resonances o f the oxidized ferredoxin displayed anti-Curie temperature dependences. Red uced T. vaginalis ferredoxin displayed hyperfine resonances both upfield an d downfield of the diamagnetic region. These resonances showed Curie temper ature dependences. Overall the hyperfine-shifted NMR spectrum of T. vaginal is ferredoxin, along with other spectroscopic properties, suggested differe nt structural properties for the active center of oxidized hydrogenosomal f erredoxins from those of other [2Fe-2S] ferredoxins. (C) 1998 Elsevier Scie nce Inc. All rights reserved.