1MEP

Crystal Structure of Streptavidin Double Mutant S45A/D128A with Biotin: Cooperative Hydrogen-Bond Interactions in the Streptavidin-Biotin System.

X-RAY DIFFRACTION

Starting Model(s)

Initial Refinement Model(s)
Type	Source	Accession Code	Details
experimental model	PDB	1SWE	PDB entry 1SWE

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, SITTING DROP	6.5	294	sodium citrate, cacodylate, pH 6.5, VAPOR DIFFUSION, SITTING DROP, temperature 294K

Crystal Properties
Matthews coefficient	Solvent content
1.87	45.61

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 50.645	α = 90
b = 97.857	β = 112.28
c = 52.168	γ = 90

Symmetry
Space Group	P 1 21 1

Diffraction

Diffraction Experiment
ID #	Crystal ID	Scattering Type	Data Collection Temperature	Detector	Detector Type	Details	Collection Date	Monochromator	Protocol
1	1	x-ray	100	IMAGE PLATE	MARRESEARCH		2001-04-01	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	SSRL BEAMLINE BL9-1	0.97	SSRL	BL9-1

Data Collection

Overall
ID #	Resolution (High)	Resolution (Low)	Percent Possible (Observed)	R Merge I (Observed)	Net I Over Average Sigma (I)	Redundancy	Number Reflections (All)	Number Reflections (Observed)	Observed Criterion Sigma (F)	Observed Criterion Sigma (I)	B (Isotropic) From Wilson Plot
1	1.65	50	99.6	0.099	14.8		57334	57334		-3

Highest Resolution Shell
ID #	Resolution (High)	Resolution (Low)	Percent Possible (All)	Percent Possible (Observed)	R Merge I (Observed)	Mean I Over Sigma (Observed)	Redundancy	Number Unique Reflections (All)
	1.65	1.68	98.5		0.542	1.5

Refinement

Statistics
Diffraction ID	Structure Solution Method	Cross Validation method	Starting model	Resolution (High)	Resolution (Low)	Number Reflections (All)	Number Reflections (Observed)	Number Reflections (R-Free)	Percent Reflections (Observed)	R-Factor (All)	R-Factor (Observed)	R-Work	R-Free	R-Free Selection Details	Mean Isotropic B
X-RAY DIFFRACTION	ISOMORPHOUS	THROUGHOUT	PDB entry 1SWE	1.65	10	57069	57069	2853	99.6	0.204	0.204	0.2012	0.2949	RANDOM

Temperature Factor Modeling
Anisotropic B[1][1]	Anisotropic B[1][2]	Anisotropic B[1][3]	Anisotropic B[2][2]	Anisotropic B[2][3]	Anisotropic B[3][3]

Coordinate Error
Structure Solution Method	Refinement High Resolution	Refinement Low Resolution
8		3881

RMS Deviations
Key	Refinement Restraint Deviation
s_approx_iso_adps	0.081
s_non_zero_chiral_vol	0.049
s_zero_chiral_vol	0.037
s_similar_adp_cmpnt	0.031
s_from_restr_planes	0.0308
s_angle_d	0.027
s_anti_bump_dis_restr	0.01
s_bond_d	0.007
s_rigid_bond_adp_cmpnt	0.002
s_similar_dist

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	3547
Nucleic Acid Atoms
Solvent Atoms	293
Heterogen Atoms	64

Software

Software
Software Name	Purpose
DENZO	data reduction
SCALEPACK	data scaling
SHELX	model building
SHELXL-97	refinement
SHELX	phasing

RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM157729.