Microbial metalloproteomes are largely uncharacterized

Metalloprotein diversity Metalloproteins are key components in many biological processes, including respiration, photosynthesis and drug metabolism. The presence of a metal in a protein is often not apparent until the molecule is fully characterized. For this reason, and because of the diversity of metal coordination sites, it is not yet possible to use genome sequences to predict the types of metal an organism utilizes from its environment, or to determine the composition of the organism's metalloproteins. Cvetkovic et al. have therefore taken an alternative route, using conventional liquid chromatography to identify the metals in an organism — the hyperthermophilic marine archaeon Pyrococcus furiosus — and proteomics to examine the metalloproteins. Of the 343 metal peaks in chromatography fractions, 158 did not match any known or predicted metalloprotein, some of them containing metals that the organism was not previously known to utilize. This work suggests that metalloproteomes are more extensive and diverse than previously thought.