8X2V

Crystal structure of the ancestral GH19 chitinase, Anc4+LoopII (P12K/N13H mutant)

X-RAY DIFFRACTION

Starting Model(s)

Initial Refinement Model(s)
Type	Source	Accession Code	Details
in silico model	AlphaFold

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, SITTING DROP		293	1 uL of Anc4+Loop II+p12K/n13H (6.0 mg/mL in 10 mM sodium acetate pH 5.0, 150 mM NaCl) + 1 uL of 25% (w/v) polyethylene glycol 3350, 0.1 M Bis-Tris, pH 6.5

Crystal Properties
Matthews coefficient	Solvent content
1.8	31.54

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 37.29	α = 90
b = 69.83	β = 90
c = 70.27	γ = 90

Symmetry
Space Group	P 2 21 21

Diffraction

Diffraction Experiment
ID #	Crystal ID	Scattering Type	Data Collection Temperature	Detector	Detector Type	Details	Collection Date	Monochromator	Protocol
1	1	x-ray	100	PIXEL	DECTRIS EIGER X 16M		2023-07-29	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	SPRING-8 BEAMLINE BL32XU	1.0	SPring-8	BL32XU

Data Collection

Overall
ID #	Resolution (High)	Resolution (Low)	Percent Possible (Observed)	CC (Half)	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	1.29	49.53	100	0.998	12.87	33.1		47133			12.41

Highest Resolution Shell
ID #	Resolution (High)	Resolution (Low)	Percent Possible (All)	Percent Possible (Observed)	CC (Half)	Mean I Over Sigma (Observed)	Redundancy	Number Unique Reflections (All)
1	1.29	1.29			0.997

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	Mean Isotropic B
X-RAY DIFFRACTION	MOLECULAR REPLACEMENT	FREE R-VALUE	1.29	49.53	1.38	47016	2000	100	0.1716	0.1709	0.186	14.9

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
f_dihedral_angle_d	5.6941
f_angle_d	0.9575
f_chiral_restr	0.0803
f_plane_restr	0.0091
f_bond_d	0.007

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	1794
Nucleic Acid Atoms
Solvent Atoms	134
Heterogen Atoms

Software

Software
Software Name	Purpose
PHASER	phasing
PHENIX	refinement
XDS	data reduction
XSCALE	data scaling

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 R01GM133198.