Membrane-bound Bacillus cytochromes c and their phylogenetic position among bacterial class I cytochromes c

Abstract Gram-positive bacteria lack a periplasmic compartment and contain only membrane-bound cytochromes c . There are at least two types. One is found in subunit II of cytochrome oxidase, and the other is small cytochrome c which is also membrane-bound because of an unprocessed signal sequence or post-translational acylation at the N-terminal end of the protein. These Bacillus cytochromes c are compared with known class I cytochromes c , and a phylogenetic tree has been constructed by the neighbour-joining method.