Table 1. Classification of lasso structures.

Lasso type	A	B	C	D	E
Single, L1	296	5	117	37	179
Double, L2	46	3	22	9	24
Triple, L3	25	3	4	8	21
Sixfold, L6	1	1	1	0	0
Supercoiling, LS	14	2	4	5	10
Two-sided, LL	10	1	2	6	8
Total	376	5	148	41	228

A – Number of proteins; B – number of enzyme groups with respect to the first number in EC classification; C – number of enzymes; D – number of non-enzyme classes with respect to PDB database; E – number of non-enzymes.