Paracoccus dentrificans

Thermodynamic Parameters of the Rieske Fragments from the be. Complexes of Bovine Heart (ISFb) (92) and Paracoccus dentrificans (ISFpd) (140) and of the Rieske-Type Ferredoxin FROM Benzene Dioxygenase (FdBED) (55)... 

The simpler cytochrome bc] complexes of bacteria such as E. coli,102 Paracoccus dentrificans,116 and the photosynthetic Rhodobacter capsulatus117 all appear to function in a manner similar to that of the large mitochondrial complex. The bc] complex of Bacillus subtilis oxidizes reduced menaquinone (Fig. 15-24) rather than ubiquinol.118 In chloroplasts of green plants photochemically reduced plastoquinone is oxidized by a similar complex of cytochrome b, c-type cytochrome /, and a Rieske Fe-S protein.119 120a This cytochrome b6f complex delivers electrons to the copper protein plastocyanin (Fig. 23-18). 

Fig. 6. Electron transfer complex between methylamine dehydrogenase and amicyanin from Paracoccus dentrificans (PDB Accession Code 2MTA). The distance shown is between eN of the redox cofactor tryptophan tryptophylquinone of methylamine dehydrogenase and the eN of the His-95 ligand of amicyanin.

The same high-field advantage appeared in an investigation of the Mn binding site in cytochrome c oxidase from Paracoccus dentrificans. Spectra taken at W-band were considerably simplified compared with X-band and revealed contributions of a dipolar interaction between the Mn " spin and the local CuA centre with a coupling constant of 33.6 G. This corresponded to an averaged distance of 9.4 0.2 A, which is consistent with the known X-ray structure of the material. 

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