Table 1. Geometrical parameters of the T-form of d(CCCTAA)^a.

Base	χ (°)	P (°)	Buckle (°)	Propeller twist (°)
C1	–146 ± 10	131 ± 50	29 ± 8	–175 ± 7
C2	–125 ± 8	58 ± 6	3 ± 3	–168 ± 3
C3	–123 ± 4	53 ± 12	4 ± 3	–177 ± 3
T4	–128 ± 11	31 ± 14	–2 ± 5	–180 ± 4
A5	–105 ± 40	100 ± 45	–8 ± 12	136 ± 58
Step	Rise (Å)	Helical twist (°)
C1–C2	6.9 ± 0.4	25 ± 4
C2–C3	6.1 ± 0.2	19 ± 5
C3–T4	6.4 ± 0.3	27 ± 3
T4–A5	6.1 ± 0.2	–8 ± 10

^aThe parameters were computed with the Curves 5.3 program (30), using the definitions therein. The values are the average ± standard deviation obtained for the seven lowest-energy structures: The χ and P parameters were obtained from 28 deoxyriboses, and the other helical parameters were from 14 parallel duplexes.