The jelly roll or Swiss roll fold is a protein fold or supersecondary structure composed of eight beta strands arranged in two four-stranded sheets. The name of the structure was introduced by Jane S. Richardson in 1981, reflecting its resemblance to the jelly or Swiss roll cake.[2] The fold is an elaboration on the Greek key motif and is sometimes considered a form of beta barrel. It is very common in viral proteins, particularly viral capsid proteins.[3][4] Taken together, the jelly roll and Greek key structures comprise around 30% of the all-beta proteins annotated in the Structural Classification of Proteins (SCOP) database.[5]