Rossmann Fold

This fold is made up of three or more parallel beta strands linked by two alpha helices in the topological order beta-alpha-beta-alpha-beta. Two Rossmann folds, wound in opposite directions create a dinucleotide binding unit found in many enzymes, specifically in nucleotide binding proteins (hence its alternative name mononucleotide-binding motif).

The example shown is a mannose permease (CATH domain ID 1pdoA00).