It’s true: the genome of Mimivirus is bigger than some bacterial genomes, but it is still a virus. Or is it?
When and where I was doing my master’s degree (and that was more than 20 years ago, at the Department of Biochemistry of Medico-Biological Faculty), we were jokingly defining life as “the mode of existence of cytochrome P450”. I’ve always thought that viruses are not alive; therefore, they don’t need P450s. Now, this paper describes the expression of a P450 gene from Mimivirus in E. coli. The CO complex of the expressed protein shows the characteristic absorption spectrum of ‘functional’ P450, but its biological function remains unknown.