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A bacterial c ‐type cytochrome can be translocated to the periplasm as an apo form; the biosynthesis of cytochrome cd 1 (nitrite reductase) from Paracoccus denitrificans
Author(s) -
Page M. D.,
Ferguson S. J.
Publication year - 1989
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1989.tb00213.x
Subject(s) - paracoccus denitrificans , biology , periplasmic space , cytochrome , nitrite reductase , biochemistry , biosynthesis , cytochrome p450 reductase , reductase , cytochrome c , coenzyme q – cytochrome c reductase , enzyme , gene , escherichia coli , nitrate reductase , mitochondrion
Summary An apo form of cytochrome cd 1 , (nitrite reductase) of Paracoccus denitrificans has been detected immunologically in the periplasm of a mutant that lacks all c ‐type cytochromes. A method for the preparation of apo‐nitrite reductase (lacking both c ‐ and d‐type haem) from the holoenzyme of wild‐type cells has been developed. The apoprotein synthesized by the mutant is indistinguishable from the chemically prepared apoprotein in respect of: (i) subunit molecular weight; (ii) formation of a homodimer; (iii) properties on anion exchange chromatography. The holoenzyme has similar properties in respect of (i) and (ii) but behaves differently during anion exchange. A suggested mode of assembly of cytochrome cd 1 , is trans‐location into the periplasm of a precursor polypeptide, maturation by a signal peptidase to give an apoprotein identical to that prepared chemically from the holoenzyme, followed by insertion of c ‐type and d‐type haem in an as yet unknown order.