1DZE

Structure of the M Intermediate of Bacteriorhodopsin trapped at 100K

Experimental procedure

Experimental method	SINGLE WAVELENGTH
Source type	SYNCHROTRON
Source details	SPRING-8 BEAMLINE BL44B2
Synchrotron site	SPring-8
Beamline	BL44B2
Temperature [K]	100
Detector technology	IMAGE PLATE
Collection date	1998-11-18
Detector	RIGAKU IMAGE PLATE
Spacegroup name	P 6 2 2
Unit cell lengths	102.400, 102.400, 112.300
Unit cell angles	90.00, 90.00, 120.00

Refinement procedure

Resolution	8.000 - 2.500
R-factor	0.257
Rwork	0.257
R-free	0.28300
Structure solution method	MOLECULAR REPLACEMENT
Starting model (for MR)	1qm8
RMSD bond length	0.006
RMSD bond angle	1.220
Data reduction software	MOSFLM
Data scaling software	SCALA
Phasing software	X-PLOR
Refinement software	X-PLOR (3.851)

Data quality characteristics

	Overall	Outer shell
Low resolution limit [Å]	50.000	2.590
High resolution limit [Å]	2.500	2.500
Number of reflections	11480
Completeness [%]	91.7	55.2
Redundancy	14.4

Crystallization Conditions

crystal ID	method	pH	temperature	details
1	VAPOR DIFFUSION	5.2		THE CRYSTALLIZATION CONSISTS OF TWO STEPS. FIRST, A MIXTURE OF 5 MG/ML PURPLE MEMBRANE, 0.25% OTG, 1 M AMMONIUM SULFATE, 0.16 M NACL, 0.04 M SODIUM CITRATE (PH5.2) , 0.04% NAN3 WAS INCUBATED AND 15% TREHALOSE AT 305K FOR 5 DAYS. THIS RESULTED IN THE FORMATION OF SPHERICAL VESICLES WITH A DIAMETER OF 50 NM. AFTER SEDIMENTAL MATERIALS WERE REMOVED BY CENTRIFUGATION (4000G X 10 MIN), A SUSPENSION OF THE SPHERICAL VESICLES WAS COOLED TO 278K AND CONCENTRATED BY VAPOR DIFFUSION AGAINST A RESERVOIR SOLUTION CONTAINING 2.0 M AMMONIUM SULFATE 0.08M SODIUM CITRATE (PH 5.2) AND 30% TREHALOSE. INCUBATION FOR A COUPLE OF MONTHS YIELDED HEXAGONAL CRYSTALS.