This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Janssen, S. Articles by Moll, R. Search for Related Content PubMed PubMed Citation Articles by Janssen, S. Articles by Moll, R.

 Previous Article  |  Next Article 

J. Bacteriol., Sep 1997, 5560-5569, Vol 179, No. 17
Copyright © 1997, American Society for Microbiology

A succinate dehydrogenase with novel structure and properties from the hyperthermophilic archaeon Sulfolobus acidocaldarius: genetic and biophysical characterization

S Janssen, G Schafer, S Anemuller and R Moll
Institute of Biochemistry, Medical University of Lubeck, Germany.

The sdh operon of Sulfolobus acidocaldarius DSM 639 is composed of four genes coding for the 63.1-kDa flavoprotein (SdhA), the 36.5-kDa iron- sulfur protein (SdhB), and the 32.1-kDa SdhC and 14.1-kDa SdhD subunits. The four structural genes of the sdhABCD operon are transcribed into one polycistronic mRNA of 4.2 kb, and the transcription start was determined by the primer extension method to correspond with the first base of the ATG start codon of the sdhA gene. The S. acidocaldarius SdhA and SdhB subunits show characteristic sequence similarities to the succinate dehydrogenases and fumarate reductases of other organisms, while the SdhC and SdhD subunits, thought to form the membrane-anchoring domain, lack typical transmembrane alpha-helical regions present in all other succinate:quinone reductases (SQRs) and quinol:ifumarate reductases (QFRs) so far examined. Moreover, the SdhC subunit reveals remarkable 30% sequence similarity to the heterodisulfide reductase B subunit of Methanobacterium thermoautotrophicum and Methanococcus jannaschii, containing all 10 conserved cysteine residues. Electron paramagnetic resonance (EPR) spectroscopic studies of the purified enzyme as well as of membranes revealed the presence of typical S1 [2Fe2S] and S2 [4Fe4S] clusters, congruent with the deduced amino acid sequences. In contrast, EPR signals for a typical S3 [3Fe4S] cluster were not detected. However, EPR data together with sequence information implicate the existence of a second [4Fe4S] cluster in S. acidocaldarius rather than a typical [3Fe4S] cluster. These results and the fact that the S. acidocaldarius succinate dehydrogenase complex reveals only poor activity with caldariella quinone clearly suggest a unique structure for the SQR of S. acidocaldarius, possibly involving an electron transport pathway from the enzyme complex into the respiratory chain different from those for known SQRs and QFRs.

This article has been cited by other articles:

• Nunoura, T., Sako, Y., Wakagi, T., Uchida, A. (2003). Regulation of the aerobic respiratory chain in the facultatively aerobic and hyperthermophilic archaeon Pyrobaculum oguniense. Microbiology 149: 673-688 [Abstract] [Full Text]  
• Iwasaki, T., Kounosu, A., Aoshima, M., Ohmori, D., Imai, T., Urushiyama, A., Cosper, N. J., Scott, R. A. (2002). Novel [2Fe-2S]-type Redox Center C in SdhC of Archaeal Respiratory Complex II from Sulfolobus tokodaii Strain 7. J. Biol. Chem. 277: 39642-39648 [Abstract] [Full Text]  
• Hagerhall, C., Magnitsky, S., Sled, V. D., Schroder, I., Gunsalus, R. P., Cecchini, G., Ohnishi, T. (1999). An Escherichia coli Mutant Quinol:Fumarate Reductase Contains an EPR-detectable Semiquinone Stabilized at the Proximal Quinone-binding Site. J. Biol. Chem. 274: 26157-26164 [Abstract] [Full Text]  
• Schafer, G., Engelhard, M., Muller, V. (1999). Bioenergetics of the Archaea. Microbiol. Mol. Biol. Rev. 63: 570-620 [Abstract] [Full Text]  
• Hettmann, T., Schmidt, C. L., Anemuller, S., Zahringer, U., Moll, H., Petersen, A., Schafer, G. (1998). Cytochrome b558/566 from the Archaeon Sulfolobus acidocaldarius. A NOVEL HIGHLY GLYCOSYLATED, MEMBRANE-BOUND B-TYPE HEMOPROTEIN. J. Biol. Chem. 273: 12032-12040 [Abstract] [Full Text]