Fumaric reductase

Fig. 6. Comparison of VTMCD spectra for biological [Fe3S4] clusters. (A) D. gigas Fdll (20) (B) P. furiosus 3Fe Fd (42) (C) A. vinelandii Fdl (70) (D) T. thermophilus 7Fe Fd (70) (E) E. coli nitrate reductase (24) (F) E. coli fumarate reductase (53) (G) spinach glutEimate synthase (25) (H) beef heart aconitase (27). Spectra were recorded at temperatures between 1.5 and 70 K with an apphed magnetic field of 4.5 T (sdl trEmsitions increase in intensity with decreasing temperature). BEmds originating from minor heme contaminEmts Eire indicated by an asterisk.

Similar difficulties have been encountered in the case of complex enzymes such as fumarate reductase and nitrate reductase from E. coli, in which substituting certain Cys ligands led to the loss of several if not all the iron-sulfur centers (171, 172). However, in the case of nitrate reductase, which possesses one [3Fe-4S] and three [4Fe-4S] centers, it was possible to remove selectively one [4Fe-4S]... 

Midpoint potential values are useful quantitites for defining the role of the various centers in the system. In some instances, these values have even been used to predict the location of the centers in the electron transfer chain, assuming that the potential increases along the chain from the electron donor to the electron acceptor. In several oxidoreductases, however, the measured potential of some centers was found to be clearly outside the range defined by the donor and the acceptor, which raised an intriguing question as to their function. This was observed, for instance, in the case of the [4Fe-4S] (Eni = -320 mV) center in E. coli fumarate reductase (249), the [3Fe-4S] + (Era = -30 mV) center in D. gigas hydrogenase (207), and the low-potential [4Fe-4S] + + (E, = 200 and -400 mV) centers in E. 

Fig. 14.1. Role ofthe pyruvate dehydrogenase complex (PDC) during aerobic/ anaerobic transitions in the development of Ascaris suum. PDC, pyruvate dehydrogenase complex AD, acyl CoA dehydrogenase ER, enoyl CoA reductase FR, fumarate reductase SDH, succinate dehydrogenase.

Kuramochi, T., Hirawake, H., Kojima, S., Takamiya, S., Furashima, R., Aoki, T., Komuniecki, R.W. and Kita, K. (1994) Sequence comparison between the flavoprotein subunit of the fumarate reductase (complex II) of the anaerobic parasitic nematode, Ascaris suum, and the succinate dehydrogenase of the aerobic, free-living nematode, Caenorhabditis elegans. Molecular and Biochemical Parasitolog 68, 177-187. 

Figure 13.16 (a) Polypeptide fold and (b) electron transfer distances in E. coli quinol-fumarate reductase, (c) intercofactor distances in the Wolinella succinogenes enzyme. (From Iverson et al., 2002. Reproduced by permission of the Journal of Biological Chemistry.)... 

Iverson, T.M., Luna-Chavez, C., Croal, L.R., Cecchini, G. and Rees, D.C. (2002) Crystallographic studies of the Eschericia coli quinol-fumarate reductase with inhibitors bound to the quinol-binding site, J. Biol. Chem., 277, 16124-16130. 

Cammack R, Patil DS, Weiner JH. 1986. Evidence that centre 2 in Escherichia coli fumarate reductase is a [4Fe-4S] cluster. Biochim Biophys Acta 870 545-51. 

Johnson MK, Morningstar JE, Cecchini G, Ackrell BAC. 1985. Detection of a tetranuclear iron sulphur centre in fumarate reductase from Escherichia coli by EPR. Arch Microbiol 131 756-62. 

Ohnishi T, Moser CC, Page CC, et al. 2000. Simple redox-linked proton-transfer design new insights from structures of quinol-fumarate reductase. Structure Folding Design 8 R23-R32. 

Thiabendazole is an antihelmintic drug with a broad spectrum of action. Although the details of its mechanism of action are not conclusively known, it seems likely that its action is mediated by the inhibition of a specific enzyme of helminthes—fumarate reductase. Thiabendazole is active with respect to most nematode infections, including... 

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