1B6B

MELATONIN BIOSYNTHESIS: THE STRUCTURE OF SEROTONIN N-ACETYLTRANSFERASE AT 2.5 A RESOLUTION SUGGESTS A CATALYTIC MECHANISM

X-RAY DIFFRACTION

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Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1		6.5		pH 6.5

Crystal Properties
Matthews coefficient	Solvent content
2.46	51

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 56.61	α = 90
b = 56.61	β = 90
c = 207.75	γ = 120

Symmetry
Space Group	P 61

Diffraction

Diffraction Experiment
ID #	Crystal ID	Scattering Type	Data Collection Temperature	Detector	Detector Type	Details	Collection Date	Monochromator	Protocol
1	1	x-ray	95	IMAGE PLATE	MARRESEARCH	MIRROR	1998-06-15	M	MAD

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	NSLS BEAMLINE X9B	0.97935, 0.97900, 0.96860	NSLS	X9B

Data Collection

Overall
ID #	Resolution (High)	Resolution (Low)	Percent Possible (Observed)	R Sym 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	3	20	85.4	6.3	14.5	5		6476

Highest Resolution Shell
ID #	Resolution (High)	Resolution (Low)	Percent Possible (All)	Percent Possible (Observed)	R-Sym I (Observed)	Mean I Over Sigma (Observed)	Redundancy	Number Unique Reflections (All)
	3	3.11	93.2		13.2	10.5	3

Refinement

Statistics
Diffraction ID	Structure Solution Method	Cross Validation method	Resolution (High)	Resolution (Low)	Cut-off Sigma (F)	Number Reflections (Observed)	Number Reflections (R-Free)	Percent Reflections (Observed)	R-Factor (Observed)	R-Work	R-Free	R-Free Selection Details	Mean Isotropic B
X-RAY DIFFRACTION	MAD	THROUGHOUT	2.5	30	2	12034	619	92.61	0.217	0.217	0.282	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]

RMS Deviations
Key	Refinement Restraint Deviation
x_dihedral_angle_d	25.37
x_angle_deg	1.442
x_improper_angle_d	1.137
x_bond_d	0.008
x_bond_d_na
x_bond_d_prot
x_angle_d
x_angle_d_na
x_angle_d_prot
x_angle_deg_na
x_angle_deg_prot
x_dihedral_angle_d_na
x_dihedral_angle_d_prot
x_improper_angle_d_na
x_improper_angle_d_prot
x_mcbond_it
x_mcangle_it
x_scbond_it
x_scangle_it

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	2471
Nucleic Acid Atoms
Solvent Atoms	132
Heterogen Atoms

Software

Software
Software Name	Purpose
PHASES	phasing
X-PLOR	refinement
DENZO	data reduction
SCALEPACK	data scaling