A HIGHLY-ACTIVE UBIQUINOL-CYTOCHROME-C REDUCTASE (BC(1) COMPLEX) FROM THE COLORLESS ALGA POLYTOMELLA SPP, A CLOSE RELATIVE OF CHLAMYDOMONAS - CHARACTERIZATION OF THE HEME-BINDING SITE OF CYTOCHROME-C(1)

作者：GUTIERREZCIRLOS EB; ANTARAMIAN A; VAZQUEZACEVEDO M; CORIA R; GONZALEZHALPHEN D

来源：Journal of Biological Chemistry, 1994, 269(12): 9147-9154.

The alga Polytomella spp. offers extraordinary advantages in the preparation of mitochondria since it lacks chloroplasts and a cell wall. In this work the mitochondrial bc(1) complex from Polytomella spp. was solubilized and purified by ion exchange chromatography. The complex was found to be composed of 10 polypeptides and exhibited high rates of ubiquinol-cytochrome c oxido-reductase activity (>300 s(-1)) sensitive to antimycin and myxothiazol. The molecular mass of the bc(1) complex from Polytomella spp. was assayed by gel filtration and estimated to be of 256,300 Da. Therefore, this complex exhibits the unique property of behaving as a monomer. Amino-terminal sequencing of cytochrome c(1) identified 7 residues, from which a deoxyoligonucleotide was designed. A second deoxyoligonucleotide was constructed based on a highly conserved region of the c(1) type cytochromes. With these probes, a fragment of the cytochrome c(1) gene was amplified by polymerase chain reaction and sequenced. The deduced sequence of the apoprotein exhibited a consensus binding site CXXCH. The data suggest that the cytochrome c(1) from Polytomella spp. differs from other protoctists like Crithidia and Euglena, i.e. it exhibits a heme binding domain structurally related to the bovine, yeast, and Neurospora c(1) type cytochromes.

• 出版日期1994-3-25