Metalloproteins may be more numerous and diverse than previously suspected, researchers report (Nature, DOI: 10.1038/
Proteins often use metals as cofactors and catalysts, but predicting which proteins incorporate which metals is difficult because of the variety of metal-binding sites found in proteins.
“There is no routine method to analyze a complement of metalloproteins,” says Nigel J. Robinson of Newcastle University, in England, who was not involved with this study. “The challenge is an important one because nearly half of the structurally characterized enzymes in the Protein Data Bank need metals, yet it is not possible to predict with certainty which proteins will use which metals.”
Indeed, most metals associated with proteins are discovered “after the fact” as people study particular proteins, says study leader Michael W. W. Adams of the University of Georgia, Athens. “We used the reverse approach,” he says. “Rather than purifying proteins and seeing what metals they contain, we purified metal peaks and then tried to see what proteins were associated with the metal.”