Abstract
The function of cytochrome c 554 of Vibrio parahaemolyticus has not yet been determined. We have determined the physicochemical properties and crystal structure of cytochrome c 554 at 1.8 Å in order to help elucidate its function. The physicochemical properties and the tertiary structure of cytochrome c 554 resemble those of dimeric cytochrome c 552 from Pseudomonas nautica, but the Vibrio genus contains no gene for nitrite reductase, cytochrome cd 1, in its genome DNA. These results raise the possibility that both cytochromes denote an electron to an electron carrier and accept an electron from same electron carrier.