Table 1.

DNA torsion angles.

Segment	Definition	Torsion Angle (°)
		64M-2 Fab dT(6-4)T a	dT(6-4)T a	B-DNA b
(6-4) Linkage c	N1−C6−C4#−C5#	−139	−
	N1−C6−C4#−N3#	39	27
	(C5 methyl)−C5−C6−C4#	−164	−163
5'-T
Glycosidic linkage	χ (O4'−C1'−N1−C2)	−135	−138	−117
Backbone	γ (O5'−C5'−C4'−C3')	103	56	54
	δ (C5'−C4'−C3'−O3')	85	80	123
	ε (C4'−C3'−O3'−P)	−110	−107	−169
	ζ (C3'−O3'−P−O5')	−84	−76	−108
3'-T
Glycosidic linkage	χ (O4'−C1'−N1−C2)	−71	−75	−117
Backbone	α (O3'−P−O5'−C5')	−71	−96	−63
	β (P−O5−C5'−C4')	−172	−177	171
	γ (O5'−C5'−C4'−C3')	35	43	54
	δ (C5'−C4'−C3'−O3')	120	100	123

^a The torsion angles of dT(6-4)T are shown for the 64M-2 Fab—dT(6-4)T complex [11] and isolated dT(6-4)T in solution [34]; ^b The mean torsion angles of double-stranded B-DNA, the so-called Drew-Dickerson dodecamer [37], are also shown as a reference; and ^c The atoms of 3'-T are marked with #.