Table 4. Comparison of the Average BII Fractions for the DDD, 1FZX, 1SK5, and 3GGI Systems; The Values for the 1I0T System Represent the Fractions of the ZI State As Measured for 5′-GpC-3′ Steps^a.

	TIP3P			OPC
	bsc0	OL15	bsc1	bsc0	OL15	bsc1
DDD	0.12	0.23	0.22	0.10	0.21	0.21
1FZX	0.09	0.18	0.17	0.08	0.15	0.16
1SK5	0.15	0.20	0.17	0.11	0.18	0.15
3GGI	0.20	0.28	0.21	0.15	0.27	0.22
ZI Population
1I0T	0.29	0.79	0.08	0.24	0.80	0.06

^aZI is defined as follows: ζ(dG) is between 240 and 360° and β(dC) is between 205 and 300°. All frames were considered for BII and ZI analysis.