Table I.

Occurrence of chirality/orientation of the supersecondary elements βℓβ, βℓα, and αℓβ in different data sets of protein structures^a [Color table can be viewed in the online issue, which is available at http://wileyonlinelibrary.com]

Loop size	βℓβ			βℓα			αℓβ
ℓ	L (%)b	R (%)b	Loop (%)c	P (%)d	A (%)d	Loop (%)c	P (%)d	A (%)d	Loop (%)c
Data25
1	75	25	0	47	53	2	97	3	1
2	100	0	40	87	13	9	88	12	7
3	85	15	6	33	67	9	71	29	18
4	67	33	16	62	38	11	66	34	20
5	9	91	15	51	49	13	62	38	15
6	35	65	6	48	52	12	57	43	10
7	57	43	3	52	48	8	57	43	8
8	62	38	3	55	45	7	57	43	6
9	59	41	2	53	47	5	57	43	4
10	59	41	2	51	49	4	62	38	3
DataEc
1	0	0	0	62	38	1	90	10	1
2	100	0	40	85	15	10	85	15	7
3	89	11	6	30	70	10	75	25	19
4	63	37	16	57	43	10	62	38	22
5	6	94	14	52	48	15	59	41	15
6	41	59	6	47	53	11	56	44	10
7	57	43	3	51	49	8	55	45	8
8	55	45	3	48	52	8	54	46	6
9	65	35	3	54	46	5	53	47	4
10	57	43	2	50	50	4	61	39	2
DataHs
1	20	80	0	44	56	1	98	2	1
2	100	0	36	90	10	9	78	22	8
3	86	14	6	29	71	10	75	25	16
4	75	25	18	64	36	9	65	35	18
5	8	92	15	54	46	16	58	42	14
6	40	60	7	39	61	14	48	52	10
7	49	51	3	54	46	8	54	46	8
8	65	35	3	53	47	6	51	49	6
9	61	39	2	61	39	4	61	39	4
10	54	46	2	49	51	4	61	39	3
DataPyr
1	0	0	0	56	44	1	100	0	1
2	100	0	45	87	13	10	84	16	11
3	74	26	8	32	68	10	83	17	23
4	55	45	18	62	38	9	73	27	24
5	5	95	9	49	51	14	66	34	14
6	30	70	5	42	58	15	64	36	8
7	44	56	2	56	44	9	56	44	5
8	37	63	3	50	50	6	57	43	4
9	62	38	2	44	56	5	62	38	2
10	33	67	1	41	59	5	62	38	2
DataSul
1	0	0	0	0	100	1	100	0	1
2	100	0	47	88	12	9	95	5	8
3	85	15	6	23	77	12	70	30	25
4	56	44	16	58	42	13	57	43	23
5	17	83	11	52	48	16	66	34	13
6	43	57	7	27	73	10	61	39	10
7	23	77	4	33	67	6	60	40	5
8	75	25	1	55	45	8	61	39	4
9	50	50	2	62	38	3	81	19	3
10	40	60	2	35	65	5	62	38	2
DataTm
1	0	0	0	64	36	2	100	0	1
2	100	0	50	89	11	10	82	18	8
3	88	12	7	30	70	11	78	22	21
4	55	45	13	57	43	12	67	33	25
5	9	91	10	50	50	14	66	34	16
6	46	54	5	48	52	12	54	46	10
7	59	41	3	49	51	8	53	47	7
8	69	31	3	56	44	6	71	29	4
9	33	67	2	65	35	4	57	43	3
10	44	56	2	34	66	4	65	35	2

^aIn the general database Data25, very high/high preferences are denoted in red, whereas medium/low preferences are denoted in cyan (see the text for definitions).

^bRelative occurrence, expressed as percentage, of the R- and L-states for a hairpin with a given loop length.

^cPercentage of motifs with a given length of the loop. The sum is lower than 100 since motifs with loops larger than 10 residues are considered in the statistics but are not reported in the table. The total number of βℓβ loops is 12458, 2222, 6615, 677, 333, and 595 for Data25, DataEc, DataHs, DataPyr, DataSul and DataTm, respectively. The total number of βℓβ loops is 9245, 2610, 3218, 751, 374, and 853 for Data25, DataEc, DataHs, DataPyr, DataSul and DataTm, respectively. The total number of αℓβ loops is 11547, 3165, 3846, 964, 467, and 1098 for Data25, DataEc, DataHs, DataPyr, DataSul and DataTm, respectively.

^dRelative occurrence, expressed as percentage, of the A- and P-states for αℓβ and βℓα motifs with a given loop length.