1C2M

RECRUITING ZINC TO MEDIATE POTENT, SPECIFIC INHIBITION OF SERINE PROTEASES

Experimental procedure

Experimental method	SINGLE WAVELENGTH
Source type	ROTATING ANODE
Temperature [K]	298
Detector technology	IMAGE PLATE
Collection date	1998-04-05
Detector	RIGAKU RAXIS IV++
Spacegroup name	P 31 2 1
Unit cell lengths	54.850, 54.850, 109.230
Unit cell angles	90.00, 90.00, 120.00

Refinement procedure

Resolution	7.500 - 1.400
R-factor	0.195
Rwork	0.195
R-free	0.23400
Structure solution method	DIFFERENCE FOURIER PLUS REFINEMENT
RMSD bond length	0.018
RMSD bond angle	3.700
Data reduction software	bioteX ((MSC))
Data scaling software	bioteX
Phasing software	X-PLOR
Refinement software	X-PLOR (3.1)

Data quality characteristics

	Overall	Outer shell
Low resolution limit [Å]	35.840	1.460
High resolution limit [Å]	1.330	1.400
Rmerge	0.085	0.345
Number of reflections	32374
<I/σ(I)>	8.2	1.6
Completeness [%]	74.0	37.4
Redundancy	2.3

Crystallization Conditions

crystal ID	method	pH	temperature	details
1	unknown *	4.98		TRYPSIN-BENZAMIDINE, P3(1) 2 1 WERE GROWN BY VAPOR DIFFUSION, AS DESCRIBED FOR P2(1) 2(1) 2(1) (LARGE CELL) (MANGEL, ET AL., BIOCHEMISTRY 29, 8351-8357, 1990) THE CRYSTAL WAS SOAKED FOR 25 DAYS IN 2.11 M ZN+2, 250 MM CL-, PH 4.86 IN THE ABSENCE OF AN INHIBITOR. THIS SOLUTION WAS REPLACED ONCE EVERY DAY OR TWO TO REMOVE BOUND BENZAMIDINE AND TO INCORPORATE ZN+2 AT THE ACTIVE SITE. IT WAS THEN SOAKED IN CHLORIDE-FREE SOLUTION OF 1.02 MGSO4 . 7H2O, 1.62 M ZNSO4 . 7 H2O, 0.50 M ZINC ACETATE DIHYDRATE, PH 4.98 FOR 10 DAYS DURING WHICH THE SOAKING SOLUTION WAS REPLACED ONCE A DAY.