1QAE

THE ACTIVE SITE OF SERRATIA ENDONUCLEASE CONTAINS A CONSERVED MAGNESIUM-WATER CLUSTER

Experimental procedure

Experimental method	SINGLE WAVELENGTH
Source type	ROTATING ANODE
Source details	RIGAKU RU200
Temperature [K]	288
Detector technology	DIFFRACTOMETER
Collection date	1998-02-02
Detector	ENRAF-NONIUS FAST
Spacegroup name	P 21 21 2
Unit cell lengths	106.700, 74.500, 68.900
Unit cell angles	90.00, 90.00, 90.00

Refinement procedure

Resolution	50.000 - 2.050
R-factor	0.167 *
Rwork	0.167
R-free	0.21000
Starting model (for MR)	1.4 ANGSTROM STRUCTURE OF THE SERRATIAL ENDONUCLEASE (CAI MILLER AND KRAUSE) WITH WATER AND ALTERNATE SIDE CHAIN CONFORMERS REMOVED AND THE SIDE CHAINS FOR THE ACTIVE SITE RESIDUES ARG 57 HIS 89 ASN 199 AND GLU 127 OMITTED
RMSD bond length	0.005
RMSD bond angle	26.600 *
Data reduction software	PROCOR
Data scaling software	PROCOR
Phasing software	X-PLOR (3.851)
Refinement software	X-PLOR (3.851)

Data quality characteristics

	Overall	Outer shell
Low resolution limit [Å]	45.000	2.100
High resolution limit [Å]	2.050	2.050
Rmerge	0.025	0.045
Total number of observations	93785 *
Number of reflections	30574
<I/σ(I)>	40.87	18.9
Completeness [%]	84.3	20.4
Redundancy	3.1	1.6

Crystallization Conditions

crystal ID	method	pH	temperature	details
1	other *	4.6 *	4 *	CRYSTALLIZATION METHOD: VAPOR DIFFUSION SITTING DROP CRYSTALLIZATION TEMPERATURE: 277 K CRYSTALLIZATION PH: 4.6 CRYSTALS WERE GROWN FROM PEG 3350, AMMONIUM SULFATE, SODIUM ACETATE, AND STORED IN A STABILIZATION SOLUTION CONTAINING 20% PEG 3000, 400mM GLYCINE, 40mM TRIS, PH8.2 (293 K), 20% PEG 3000, 10% PEG 400. THIS SOLUTION WAS EXCHANGED THREE TIMES TO MINIMIZE CARRY OVER FROM THE STORAGE SOLUTION. AFTER 3 DAYS IN THE MAGNESIUM STABILIZATION SOLUTION, THE CRYSTAL OF DIMENSION 0.4 X 0.4 X 0.3 MM**2 WAS MOUNTED IN A SILICONIZED SPECIAL GLASS CAPILLARY. , VAPOR DIFFUSION, SITTING DROP

Crystallization Reagents in Literatures

ID	crystal ID	solution	reagent name	concentration (unit)	details
1	1	1	PEG3350	15 (%(w/v))
2	1	1	ammonium sulfate	0.2 (M)
3	1	1	sodium acetate	0.1 (M)