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Key slides
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Holton J. M. and Frankel K. A. (2010) Acta D66, 393–408
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Optimum exposure time (faint spots) t hr optimum exposure time for data set (s) t ref exposure time of reference image (s) bg ref background level near weak spots on reference image (ADU) bg 0 ADC offset of detector (ADU) σ 0 rms read-out noise (ADU) gain ADU/photon m multiplicity of data set (including partials) Short answer: bg hr = 90 ADU for ADSC Q315r Holton J. M. and Frankel K. A. (2010) in preparation
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Point Spread Function pixel intensity (ADU) distance from “point” (mm) 10 7 10 6 10 5 10 4 10 3 100 10 1 0.01 0.1 1 2 re-sampled sum scaled and shifted I ~ g(r 2 +g 2 ) -3/2 g = 30 μm Holton J. M. and Frankel K. A. (2010) in preparation
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Spatial Noise: Q315r vs Pilatus Holton, Frankel, Gonzalez, Waterman and Wang (2010) in preparation 3.5 3.0 2.5 2.0 1.5 1.0 0.5 average change in spot intensity (%) distance between spots (mm) 0.1 1 10 100 Pilatus Q315r anomalous differences typically > 100 mm apart!
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Radiation damage = Kanzaki force?
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scaled (sin(θ)/λ) 2 APE1 Wilson plot 4.1 3.5 3.2 2.9 2.7 2.5 2.4 2.2 2.1 resolution (Å) R cryst /R free 0.355/0.514 0.257/0.449 0.209/0.407 Tsutakawa et al. (2010) in preparation
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Simulated diffraction image MLFSOM simulatedreal
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20% 2 + 5% 2 = 20.6% 2 R cryst + R merge ≈ R cryst The “R factor Gap” in MX
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Supporting slides
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Web calculator for experiment success/failure
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Holton J. M. and Frankel K. A. (2010) Acta D66, 393–408
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Where: I DL - average damage-limited intensity (photons/hkl) at a given resolution 10 5 - converting R from μm to m, r e from m to Å, ρ from g/cm 3 to kg/m 3 and MGy to Gy r e - classical electron radius (2.818 x 10 -15 m/electron) h- Planck’s constant (6.626 x 10 -34 J∙s) c- speed of light (299792458 m/s) f decayed - fractional progress toward completely faded spots at end of data set ρ- density of crystal (~1.2 g/cm 3 ) R- radius of the spherical crystal (μm) λ- X-ray wavelength (Å) f NH - the Nave & Hill (2005) dose capture fraction (1 for large crystals) n ASU - number of proteins in the asymmetric unit M r - molecular weight of the protein (Daltons or g/mol) V M - Matthews’s coefficient (~2.4 Å 3 /Dalton) H- Howells’s criterion (10 MGy/Å) θ- Bragg angle a 2 - number-averaged squared structure factor per protein atom (electron 2 ) M a - number-averaged atomic weight of a protein atom (~7.1 Daltons) B- average (Wilson) temperature factor (Å 2 ) μ- attenuation coefficient of sphere material (m -1 ) μ en - mass energy-absorption coefficient of sphere material (m -1 ) Theoretical limit: Holton J. M. and Frankel K. A. (2010) Acta D66, 393–408
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Other radiation damage limits Holton J. M. (2009) J. Synchrotron Rad. 16 133-42 MW (kDa) Resolution (Å) V M (Å 3 /Da) Wilson B (Å 2 ) Crystal size (μm) No. of xtals n0n0 reference 62 ? [1] [1] 1.92.4?20*3013130 Gonzalez & Nave 1994 141.62.022*35125 Teng & Moffat 2000 282.12.53020112 Glaeser et al. 2000 242.02.5225x30x3059.8 Facciotti et al. 2003 4003.52.565*2019.3 Sliz et al. 2003 28.61.981.5811525.2 Coulibaly et. al. 2007 0.81.31.510 1.5x1.5x5 33.7 Nelson et al. 2005 Sawaya et al. 2007 782.653.065616 [2] x5x5 [2]43.6 Li et al. 2004 733.43.67695133.2 Standfuss et al. 2007 211.52.411.41x1x20903.1 Moukhametzianov et al. 2008 60003.463.470 17180 Schuwirth et al. 2005 [1] [1] Estimated for 100 Å unit cell in P4 3 2 1 2 with V M = 2.4 [2] [2] Taken from 400 um 3 illuminated volume quoted by Moukhametzianov et al. (2008) and 5 um beam
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Background level sets needed photons/spot Moukhametzianov et al. (2008). Acta Cryst. D 64, 158-166
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Point-spread function of ADSC detectors
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“realistic” PSF “no” PSF Point Spread Function
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pixel intensity (ADU) distance from “point” (mm) 10 7 10 6 10 5 10 4 10 3 100 10 1 0.01 0.1 1 2 re-sampled sum scaled and shifted Gaussians Holton J. M. and Frankel K. A. (2010) in preparation
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Point Spread Function pixel intensity (ADU) distance from “point” (mm) 10 7 10 6 10 5 10 4 10 3 100 10 1 0.01 0.1 1 2 re-sampled sum scaled and shifted I ~ r 3 Holton J. M. and Frankel K. A. (2010) in preparation
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Point Spread Function pixel intensity (ADU) distance from “point” (mm) 10 7 10 6 10 5 10 4 10 3 100 10 1 0.01 0.1 1 2 re-sampled sum scaled and shifted I ~ g(r 2 +g 2 ) -3/2 g = 30 μm Holton J. M. and Frankel K. A. (2010) in preparation
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active area of CCD phosphor sheet severed fibers intact fibers X-ray beam taper-taper barrier spot flood field Holton J. M. and Frankel K. A. (2010) in preparation
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pixel intensity (ADU) distance from “point” (CCD pixels) 10 5 10 4 10 3 100 10 1 Holton J. M. and Frankel K. A. (2010) in preparation
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Optimum exposure time calculator
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Optimum exposure time (faint spots) t hr optimum exposure time for data set (s) t ref exposure time of reference image (s) bg ref background level near weak spots on reference image (ADU) bg 0 ADC offset of detector (ADU) σ 0 rms read-out noise (ADU) gain ADU/photon m multiplicity of data set (including partials) Short answer: bg hr = 90 ADU for ADSC Q315r Holton J. M. and Frankel K. A. (2010) in preparation
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Detector spatial noise dominates anomalous difference errors
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Optimum exposure time (anomalous differences) Holton J. M. and Frankel K. A. (2010) in preparation
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Optimum exposure time (anomalous differences) I-I+ 3% 100 photons 10 photons 100 photons Holton J. M. and Frankel K. A. (2010) in preparation
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Optimum exposure time (anomalous differences) I-I+ 3% 100 photons 14 photons 100 photons Holton J. M. and Frankel K. A. (2010) in preparation
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Optimum exposure time (anomalous differences) 3% I-I+ 2000 photons 67 photons Holton J. M. and Frankel K. A. (2010) in preparation
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Optimum exposure time (anomalous differences) 1% I-I+ 20,000 photons 200 photons Holton J. M. and Frankel K. A. (2010) in preparation
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Minimum required signal (MAD/SAD) Holton J. M. and Frankel K. A. (2010) in preparation
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Spatial Noise Holton, Frankel, Gonzalez, Waterman and Wang (2010) in preparation
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Spatial Noise down Holton, Frankel, Gonzalez, Waterman and Wang (2010) in preparation
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Spatial Noise downup Holton, Frankel, Gonzalez, Waterman and Wang (2010) in preparation
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Spatial Noise downup R separate Holton, Frankel, Gonzalez, Waterman and Wang (2010) in preparation
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Spatial Noise oddeven R mixed Holton, Frankel, Gonzalez, Waterman and Wang (2010) in preparation
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Spatial Noise separate:2.5% Holton, Frankel, Gonzalez, Waterman and Wang (2010) in preparation
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Spatial Noise separate: mixed: 2.5% 0.9% Holton, Frankel, Gonzalez, Waterman and Wang (2010) in preparation
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Spatial Noise separate: mixed: 2.5% 0.9% 2.5% 2 -0.9% 2 = 2.3% 2 Holton, Frankel, Gonzalez, Waterman and Wang (2010) in preparation
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Spatial Noise mult > ( — ) 2 2.3% Holton, Frankel, Gonzalez, Waterman and Wang (2010) in preparation
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Spatial Noise mult > ( — ) 2 R merge Holton, Frankel, Gonzalez, Waterman and Wang (2010) in preparation
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Spatial Noise Holton, Frankel, Gonzalez, Waterman and Wang (2010) in preparation
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Spatial Noise Holton, Frankel, Gonzalez, Waterman and Wang (2010) in preparation
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Spatial Noise
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Holton, Frankel, Gonzalez, Waterman and Wang (2010) in preparation
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Spatial Noise: Q315r vs Pilatus Holton, Frankel, Gonzalez, Waterman and Wang (2010) in preparation 3.5 3.0 2.5 2.0 1.5 1.0 0.5 average change in spot intensity (%) distance between spots (mm) 0.1 1 10 100 Pilatus Q315r anomalous differences typically > 100 mm apart!
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Diffraction image simulation for tying it all together
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Simulated diffraction image MLFSOM simulatedreal
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Sources of noise “photon counting” Read-out noise Shutter jitter Beam flicker spot shape radiation damage σ(N) = sqrt(N) rms 11.5 e-/pixel rms 0.57 ms 0.15 %/√Hz pixels? mosaicity? B/Gray?
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The R-factor Gap MLFSOM Elves R merge = 6% R cryst = 17% R free = 20% multi-conformer PDB file 1H87
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The R-factor Gap MLFSOM Elves R merge = 6% R cryst = 7% R free = 8% multi-conformer PDB file 1H87
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The R-factor Gap MLFSOM Elves R merge = 6% R cryst = 7% R free = 8% single-conformer PDB file 1H87; conf “A”
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Sources of noise “photon counting” Read-out noise Shutter jitter Beam flicker spot shape radiation damage σ(N) = sqrt(N) rms 11.5 e-/pixel rms 0.57 ms 0.15 %/√Hz pixels? mosaicity? B/Gray?
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Where is the rest of it? 20% 2 + 5% 2 = 20.6% 2 R cryst + R merge ≈ R cryst
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Radiation damage http://bl831.als.lbl.gov/~jamesh/ribo_blast/ Howells et al. (2009) J. Electron. Spectrosc. Relat. Phenom. 170 4-12
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resolution (Å) maximum tolerable dose (MGy) 1 2 3 5 7 10 20 40 70 100 1 10 100 10 3 Howells et al. (2009) J. Electron. Spectrosc. Relat. Phenom. 170 4-12 resolution dependence of radiation damage
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resolution (Å) maximum tolerable dose (MGy) 1 2 3 5 7 10 20 40 70 100 1 10 100 10 3 Howells et al. (2009) J. Electron. Spectrosc. Relat. Phenom. 170 4-12 resolution dependence of radiation damage
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10 MGy/Å what the is a MGy? http://bl831.als.lbl.gov/ damage_rates.pdf Holton J. M. (2009) J. Synchrotron Rad. 16 133-42
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Radiation Damage Model I- average observed spot intensity I 0 - intensity of “undamaged” spot dose- absorbed dose (MGy) H - 10 MGy/Å d- resolution of spot (Å) I = I 0 exp(-ln(2) ) global (lattice) damage dose d∙H
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Radiation Damage Model I- average observed spot intensity I 0 - intensity of “undamaged” spot dose- absorbed dose (MGy) H - 10 MGy/Å d- resolution of spot (Å) I = I 0 exp(-ln(2) ) global (lattice) damage dose d∙Hd∙H 10 MGy/Å
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Radiation Damage Model accumulated dose (MGy) normalized total intensity
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Radiation Damage Model accumulated dose (MGy) normalized total intensity
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accumulated dose (MGy) relative B factor data taken from Kmetko et. al. 2006 Radiation Damage Model
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accumulated dose (MGy) relative B factor data taken from Kmetko et. al. 2006 Radiation Damage Model
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accumulated dose (MGy) relative B factor data taken from Kmetko et. al. 2006 Radiation Damage Model
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I- average observed spot intensity I 0 - intensity of “undamaged” spot dose- absorbed dose (MGy) H - 10 MGy/Å d- resolution of spot (Å) I = I 0 exp(-ln(2) ) global (lattice) damage dose d∙H
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Radiation Damage Model F- rms observed structure factor F 0 - F of “undamaged” crystal dose- absorbed dose (MGy) H - 10 MGy/Å s- 0.5/d d- resolution of spot (Å) F = F 0 exp(-ln(2) s ) global (lattice) damage dose H
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Radiation Damage Model F- rms observed structure factor F 0 - F of “undamaged” crystal B- canonical Debye-Waller factor s - 0.5/d d- resolution of spot (Å) F = F 0 exp( - B∙s 2 ) global (lattice) damage
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Radiation Damage Model F- rms observed structure factor F 0 - F of “undamaged” crystal A- ln(2)*dose/H H - 10 MGy/Å s - 0.5/d d- resolution of spot (Å) F = F 0 exp( - A∙s ) global (lattice) damage
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Debye-Waller-Ott factor James R. W. (1962) Optical Principles of the Diffraction of X rays. Ox Bow press.
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Radiation Damage Model A- something Debye said was zero B- canonical Debye-Waller factor C- something else Debye said was zero s - 0.5/d d- resolution of spot (Å) F = F 0 exp( - A∙s - B∙s 2 - C∙s 3 - … ) global (lattice) damage
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Radiation Damage Model F- rms observed structure factor F 0 - F of “undamaged” crystal dose- absorbed dose (MGy) H - 10 MGy/Å s- 0.5/d d- resolution of spot (Å) F = F 0 exp(-ln(2) s ) global (lattice) damage dose H
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Radiation Damage Model normalized total intensity Resolution (Ǻ) 5 2.5 1.7 1.25 1.0 Gaussian Exponential Reciprocal Space
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Radiation Damage Model normalized number of atoms magnitude of displacement (Å) Lorentzian Gaussian Direct Space
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Radiation Damage Model How can the distribution of atom displacements from radiation damage NOT be Gaussian? (central limit theorem) what can cause a Lorentzian distribution?
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Macroscopic damage http://bl831.als.lbl.gov/~jamesh/ribo_blast/
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crystal expansion Protein crystal in sucrose, NaWO4 and oil
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crystal expansion Protein crystal in sucrose, NaWO4 and oil
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crystal expansion Protein crystal in sucrose, NaWO4 and oil
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crystal expansion Protein crystal in sucrose, NaWO4 and oil
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Distention of cryo with dose
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before
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Distention of cryo with dose after
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Leapman, R. D. & Sun, S. (1995). Ultramicroscopy, 59, 71–79. Distention of cryo with dose High pressure hydrogen bubbles
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Radiation Damage Model
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Kanzaki 1957
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Radiation Damage Model Kanzaki 1957
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stress and strain intensity resolution (Å) 10 5 3 2.7 2.5 2.0 1.8 1.5
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stress and strain intensity resolution (Å) 10 5 3 2.7 2.5 2.0 1.8 1.5
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stress and strain R bubble R sphere t skin 4/3 π R bubble 3 = 4 π R sphere 2 t skin u x = dR R x /R sphere F = 8π Y R sphere dR dt/t skin = 2 dR/R sphere P bubble = 2/3 Y
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stress and strain
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normalized number of atoms magnitude of displacement (fractional) stress and strain
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normalized number of atoms magnitude of displacement (fractional) stress and strain
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normalized number of atoms magnitude of displacement (fractional) stress and strain
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scaled (sin(θ)/λ) 2 APE1 Wilson plot 4.1 3.5 3.2 2.9 2.7 2.5 2.4 2.2 2.1 resolution (Å) R cryst /R free 0.355/0.514
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scaled (sin(θ)/λ) 2 APE1 Wilson plot 4.1 3.5 3.2 2.9 2.7 2.5 2.4 2.2 2.1 resolution (Å) R cryst /R free 0.355/0.514 0.257/0.449 0.209/0.407
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scaled (sin(θ)/λ) 2 APE1 Wilson plot 4.1 3.5 3.2 2.9 2.7 2.5 2.4 2.2 2.1 resolution (Å) R cryst /R free 0.355/0.514 0.257/0.449 0.209/0.407
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