In 2013, we published the structure of the first 'Toblerone'-fold protein, the cyanuric acid hydrolase from a herbicide eating bacterium (Pseudomonas sp. strain ADP). We named it the Toblerone fold because of its three-fold rotational symmetry, which is seen in both the gross structure and the active site architecture (and also in the yummy Swiss chocolate).
This week in AEM Accepts, at Applied and Environmental Microbiology, we published two brand new Toblerone-fold enzymes: a barbituric acid hydrolase and an enzyme of no known function (although we're pretty sure it's not a cyanuric acid hydrolase, nor a barbituric acid hydrolase). As well as confirming that this is a structural family of proteins, we uncovered some interesting features, such as an unusual pair of vicinal disulphide bonds in one of the enzymes that can be reversibley oxidised and reduced.