Table 3. Detailed and Simplified DISICL Classes for Protein Classification and Their Abbreviations (code)^a.

DISICL detailed classes				DISICL simple classes
structure class	code	occ. (%)	length	structure class	code	occ. (%)	length
3/10-helix	3H	3.8	2.2	3-helical turns	3HT	9.0	2.5
turn type 1	T1	2.8	2.2
turn-cap	TC	2.3	2.0
α-helix	αH	27.2	7.2	α helical	HEL	32.2	5.4
π-helix	πH	0.4	2.1
helix-cap	HC	4.6	2.0
ext. β-strand	EβS	2.7	2.4	β-strand	BS	21.3	3.9
normal β-strand	NβS	10.2	3.3
β-cap	BC	8.4	2.4
PP helical	PP	2.8	2.3	irreg. β struct.	IRB	4.7	2.2
β bulge	BU	1.9	2.1
turn type 2	T2	0.8	2.0	β turns	BT	1.4	2.0
turn type 8	T8	0.6	2.0
γ turns	GXT	1.0	2.1	other tight turns	OTT	4.5	2.2
Schellman turn	SCH	2.6	2.2
hairpin 2:2	HP	1.0	2.0
left turn 2	LT2	0.2	2.0	left-handed turns	LHT	0.6	2.0
left-handed helix	LHH	0.4	2.1
unclassified	UC	26.3	3.3	unclassified	UC	26.3	3.2

^aOccurrence (occ.) and average structure element length are calculated for combined X-ray and NMR data sets.