Discovering a whole new family of copper-binding proteins

While studying a class of copper-containing enzymes, a team of researchers discovered and characterised a new family of fungal proteins.

Their study has now been published on Nature Chemical Biology, including analysis performed at BioMAX. The article is published together with a parallel study that sheds light on one of the potential biological roles of the proteins in this new family.

In contrast with a certain romanticised idea of research, scientific discoveries seldom come with a shouted “eureka!” as to mark the end of a linear intellectual endeavour. Much more frequently, new scientific findings emerge from observations where a scientist’s first reaction might sound like “that’s odd…”. Perhaps that was how the authors of this study reacted when they realised what they were looking at wasn’t what they were looking for.

In an article published this week on Nature Chemical Biology, a team of scientists from INRA, University of Copenhagen, Marseille Université, and University of York characterised a new family of proteins, named X325, found in various fungal lineages. The article is published together with a parallel study in which one protein of this new family, Bim1, is described as involved in fungal meningitis.

The authors were initially searching for new lytic polysaccharide monooxygenases (LPMOs), copper-dependent enzymes specialised in the degradation of polysaccharides and widely used in the production of biofuels. The proteins of this new family seemed promising candidates since they share many structural features and a probable common ancestor with LPMOs. However, the researchers proved that the members of this LPMO-like protein family are not involved in polysaccharides degradation, but they more likely play a role in the regulation of copper ion content in the organisms where they are expressed.

>Read more on the MAX IV website

Image: Copper binding site of two different proteins. Left: LaX325 protein belonging to the newly identified LPMO-like protein family X325. Right: cellulose cleaving LPMO enzyme TaAA9.
Image developed by Tobias Tandrup, University of Copenhagen.