Table 1.

PTGL content

Graph type	Total	Different	Non-bifurcated	Barrels
α–β	606 816	77 127	2432	666
α	636 820	29 984	680	191
β	199 122	13 418	2246	696

The first column indicates the type of the folding graph. ‘Total’ gives the total amount of folding graphs of the particular graph type; ‘different’ the amount of different graphs among the total number; ‘non-bifurcated’ the number of different non-bifurcated graphs including barrels; and ‘barrels’ the number of different barrel structures.