The Rossmann fold is a proteinstructural motif found in proteins that bind nucleotides, especially the cofactorNAD. The structure with two repeats is composed of six parallel beta strands linked to two pairs of alpha helices in the topological order beta-alpha-beta-alpha-beta. Because each Rossmann fold can bind one nucleotide, binding domains for dinucleotides such as NAD consist of two paired Rossmann folds that each bind one nucleotide moiety of the cofactor molecule. Single Rossmann folds can bind mononucleotides such as the cofactor FMN.
The motif is named for Michael Rossmann, who first pointed out that this is a frequently occurring motif in nucleotide binding proteins, such as dehydrogenases.
In 1989, Israel Hanukoglu from the Weizmann Institute of Science discovered that the consensus sequence for NADP binding site in some enzymes that utilize NADP differs from the NAD binding motif. This discovery was used to re-engineer coenzyme specificities of enzymes.