Primary structure of a high potential iron sulfur protein from a moderately halophilic denitrifying coccus

The occurrence of a specific high potential iron-sulfur protein in a halophilic, denitrifying coccus provisionally assigned to the genus Paracoccus has been confirmed through primary structure determination. This protein, known as "HiPIP", has been found previously only in photosynthetic bacteria. The sequence of this 71-residue protein is as similar to the HiPEPs from photosynthetic bacteria as they, in turn, are to one another (average number of identically matching residues is 38%). Paracoccus HiPIP is a highly acidic protein in accord with general observations on the proteins of halophilic bacteria. A possible explanation for its occurrence in Paracoccus is that gene transfer is involved.