Table I.

Turn Properties and Roles in Protein Folding^a

Protein (PDB ID)	Turnb	Conservationc	Predicted Turn Propensityd		Properties of Peptide Model	Ref.
Protein G B1 Domain (1gb1)	(1) 9GKTL12	4.75	2.244		Strong native propensity of the second turn fragment	71,73
	(2) 47DATK50	7.00	4.494
Protein L B1 Domain (1k50)	(1) 13ANGS16	5.25	3.385		Weak native-like propensities of both turns	66,71,74
	(2) 51ADKG54	1.00	2.961
Ubiquitin (1ubq)	(1) 7TLTG10	7.00	2.838		N-terminal hairpin stable in aqueous methanol and in water	79,80,84,85
	(2) 18EPSD21	2.00	4.423
	(3) 38PDQQ41	4.50	1.834
	(4) 45FAGK48	5.50	1.599
	(5) 51EDGR54	3.75	2.532
	(6) 62QKES65	3.50	2.533
Titin I band 27th Domain (1tit)	(1) 14FVGE17	4.50	2.811		—	87,88
	(2) 36LKGQ39	6.50	5.037
	(3) 44SPDC47	4.00	2.494
	(4) 51EDGK54	4.75	3.800
	(5) 65LGMT68	5.00	e
	(6) 75AANA78	3.00	2.650
Pin1 WW Domain (1pin)	(1) 17RSSG20	5.50	7.322		—	89,92,93, 94
	(2) 26NHIT29	5.50	6.226
SH3 Domain (1srm)	(1) 20TETD23	3.75	2.388		Diverging turn (27–30) and distal hairpin (49–52) fragments have native-like conformations	69,70,96, 98,101,102
	(2) 27KKGE30	5.00	2.594
	(3) 38TEGD41	4.75	3.187
	(4) 49TTGQ52	2.75	2.417
CRABP I (1cbr)	(1) 46DGDQ49	4.50	2.490			123–125
	(2) 56TTVR59	6.25	2.786		Strong native-like propensity of 3rd and 4th hairpin fragments
	(3) 66KVGE69b	6.25	1.197
	(4) 75TVDG78	7.80	2.269
	(5) 89NENK92	4.50	2.387
	(6) 102GDGP105	3.25	3.454f
	(7) 114ANDE117	2.75	2.244
	(8) 124ADDV127	2.75	2.426

^aTurns shown by protein engineering to form before the transition state in bold italic font.

^bIdentified based on structure using DSSP¹³² and checked by criteria in Stride.¹³³

^cAverage of the conservation scores of the individual turn residues obtained using ConSurf.¹³⁴

^dPropensities to form a turn calculated using COUDES.⁴⁸

^eNot predicted as a turn in COUDES.

^fPredicted turn sequence is within the Ω-loop.