Table 1.

Rise/basepair of DNA with different G·C content in buffer and low-humidity conditions as determined with optical tweezers

	l0, rise/bp (Å/bp)
Solution condition	pBACgus11 (48% G·C)	piJ702 (70% G·C)
Buffer∗	3.38 ± 0.07 (13)	3.38 ± 0.15 (22)
30% EtOH	3.37 ± 0.11 (6)	3.36 ± 0.16 (12)
90% EtOH	3.24 ± 0.27 (18)	3.27 ± 0.35 (18)
60% EtOH + 7 μM spm4+	3.28 ± 0.15 (9)	3.11 ± 0.21 (14)

Results are reported as the mean ± SD. Numbers in parentheses indicate the population. spm, spermine.

^∗Mean values in buffer are assigned to the canonical B-form rise/basepair (2), whereas the SD values in buffer are those measured from adsorbed molecules on mica with atomic force microscopy (see accompanying article (47)).