Table 1.

Crystal forms and crystallization conditions for EcoRV-DNA complexes

Form	Space group	DNA	Cell dimensions	Crystallization conditions	pH
Nonspecific*	P21	CGAGCTCG	a = 68.4 Å; b = 79.6 Å; c = 66.4 Å; β = 104.6°	0.02 M Mes 0.1 M NaCl 1.0–1.5% PEG 4,000	6.0
I. Cognate*	C2221	GGGATATCCC	a = 60.2 Å; b = 78.4 Å; c = 371.3 Å	0.01 M sodium phosphate 0.08 M NaCl 2.5–3.5% PEG 4,000	7.0
II. Cognate	C2221	GAAGATATCTTC	a = 72.6 Å; b = 120.4 Å; c = 182.7 Å	1.5 M ammonium sulfate	5.0
III. Cognate†	P1	AAAGATATCTT	a = 49.2 Å; b = 50.4 Å; c = 64.1 Å; α = 96.4°; β = 108.9°; γ = 108.5°	0.1 M Hepes 0.15 M NaCl 10% PEG 4,000	7.5
IV. Cognate	P41212	AAGATATCTTA	a = b = 66.1 Å; c = 299.3 Å	0.1 M acetate 0.2 M Na, K tartrate 10% PEG 4,000	4.5

PEG, polyethylene glycol. 

^*From ref. 9. For the nonspecific complex, the hexameric site is 5′-TCGCGA, arising from two abutted 8-mer DNA duplexes. The central phosphates at the GC step are thus missing in this complex. Both form I and the nonspecific complex are determined at 3.0-Å resolution. 

^†From refs. 10 and 11. Form III is determined at 2.0-Å resolution.