Nitrate reductase amino acid sequences

It was long believed that bacteria were unique in their ability to denitrify. However, Shoun and Tanimoto (1991) and Shoun et al., (1989) demonstrated that the fungus, Fusarium oxysporum, could be induced to synthesize an enzyme system capable of the anaerobic reduction of nitrite to N2O. Induction occurred under conditions of low oxygen concentrations in the presence of nitrate or nitrite. One and pethaps the only component of this nitrite reductase system is a unique, soluble cytochrome P-450 (P-450dNIR), which is more similar in its cDNA-inferred amino acid sequence to soluble, bacterial P-450 enzymes (espe-... 

Labeyrie et al. (41) isolated a trypsin fragment of 11 kDa from S. cerevisiae flavocytochrome 62 that contained heme but was devoid of flavin and had no lactate dehydrogenase activity. The fragment, which was referred to as cytochrome 62 core, was found to have spectral properties very like those of microsomal cytochrome 65 (41). This similarity with cytochrome 65 is borne out by comparisons of amino acid sequence (42-44). The sequence similarity extends to related heme domains of sulfite oxidase (45, 46) and assimilatory nitrate reductase (47). The existence of a protein family with a common cytochrome 65 fold was suggested by Guiard and Lederer (48) and this is supported by the close similarity between the three-dimensional structures of microsomal cytochrome 65 (49) and the cytochrome domain of flavocytochrome 62 (23-25). 

Amino acid sequence comparisons have shown that sulfite oxidase is related to the heme-containing assimilatory nitrate reductases with a 31 % identity. Therefore, the nature of the crystal structure of chicken liver sulfite oxidase has added relevance. The crystal structure of chicken liver oxidase at... 

Fig. 3. Schematic diagram of the Arabidopsis thaliana nitrate reductase domains and the amino acid homology with nitrate reductases from other species and other proteins. Arabidopsis thaliana amino acid sequence is from Crawford et al. (1988). Other sequence data are as follows Nicotiana tabacum, Nia 2, N. sylvestris type (Vaucheret et al., 1989b) Hordeum vu/ ore(K. M. Schnorr, A. Kleinhofs, and R. L. Warner, unpublished data) Oryza sativa (Choi et al., 1989) Aspergillus nidulans (Kinghom and Campbell, 1989) rat liver sulfite oxidase (Rlso) (Crawford et al., 1988) chicken microsomal cytochrome (CM cyt b5) (Ndbrega and Ozols, 1971) cytochrome bf reductase, bovine (Ozols et al., 1985) cytochrome reductase, human (Yubisui et al., 1984).

Derived Amino Acid Sequence Homology Comparison for Several Nitrate Reductases from Different Sources ... 

Figure 3 Sequence alignment of the N-termini of ArrA and molybdenum-containing proteins. The sequences belong to the arsenate reductase of Chrysiogenes arsenatis C.a ArrA) (14), the polysulfide reductase of WoUnella succinogenes (Wii. PsrA), and the periplasmic nitrate reductases of Escherichia coli (E.c. NapA) and Pseudomonas sp. G-179 P.s. sp. NapA). Boxed amino acids show identity to C. arsenatis ArrA.

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