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Why do c ‐type cytochromes exist?
Author(s) -
Wood Paul M.
Publication year - 1983
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(83)80289-0
Subject(s) - periplasmic space , covalent bond , electron transport chain , cytochrome , cytochrome c , chemistry , biochemistry , cytoplasm , biology , enzyme , gene , escherichia coli , mitochondrion , organic chemistry
The hypothesis presented is that the different classes of c ‐type cytochrome originated as proteins located in the bacterial periplasmic space, or on the periplasmic side of the cytoplasmic membrane. In these locations, covalent bonds between haem and protein prevented the haem from being lost to the surrounding medium. Subsequent evolution has led to internal location of c ‐type cytochromes in eucaryotes and cyanobacteria. The covalent links have been retained because of their structural role; a b ‐type cytochrome could be created with similar molecular properties, but its formation would require a large evolutionary jump. If this hypothesis is correct, it should be useful in unravelling electron transport chains with unconventional donors or acceptors. Apparent exceptions deserve further investigation.