Properties of the iron-sulfur center in the 25-kilodalton subunit of the proton-translocating NADH-quinone oxidoreductase of Paracoccus denitrificans.
The 25-kDa subunit of the proton-translocating NADH-quinone oxidoreductase (NDH-1) of Paracoccus denitrificans has been expressed in Escherichia coli and purified to homogeneity. EPR studies of the reduced recombinant protein indicated that the expressed subunit contains a single [2Fe-2S] cluster (Yano, T., Sled', V. D., Ohnishi, T., and Yagi, T. (1994) Biochemistry 33, 494-499). In this report, the electronic, magnetic, and vibrational properties of the [2Fe-2S]2+,+ center have been investigated by the combination of absorption, circular dichroism, variable-temperature magnetic circular dichroism, electron paramagnetic resonance, and resonance Raman spectroscopies and compared with a range of simple [2Fe-2S]-containing proteins. The results are consistent with coordination by two cysteinyl residues at both the reducible and nonreducible iron sites and reveal a striking similarity between the properties of the [2Fe-2S] cluster in the P. denitrificans NDH-1 25-kDa subunit and those of the subclass of ferredoxin-type [2Fe-2S] centers typified by Clostridium pasteurianum 2Fe ferredoxin. The four cyteines residues involved in cluster ligation in these proteins have been tentatively identified based on sequence homology considerations.
Crouse
B R
BR
Department of Chemistry, University of Georgia, Athens 30602.
Yano
T
T
Finnegan
M G
MG
Yagi
T
T
Johnson
M K
MK
D000595:Amino Acid Sequence; D001692:Biological Transport; D002942:Circular Dichroism; D004563:Electrochemistry; D004578:Electron Spin Resonance Spectroscopy; D004926:Escherichia coli / Q000235:genetics; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000378:metabolism*; D008280:Magnetics; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010231:Paracoccus denitrificans / Q000201:enzymology*; D011522:Protons; D011808:Quinone Reductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins; D017386:Sequence Homology, Amino Acid; D013056:Spectrophotometry, Ultraviolet; D013059:Spectrum Analysis, Raman
D007506:Iron-Sulfur Proteins; D011522:Protons; D011994:Recombinant Proteins; C041831:NADH dehydrogenase (quinone); D011808:Quinone Reductases