Modelling dynamics in protein crystal structures by ensemble refinement

  1. B Tom Burnley
  2. Pavel V Afonine
  3. Paul D Adams
  4. Piet Gros  Is a corresponding author
  1. Utrecht University, The Netherlands
  2. Lawrence Berkeley National Laboratory, United States
  3. University of California Berkeley, United States
14 figures and 5 tables

Figures

Example of ensemble refinement for dataset 1UOY. (A) Optimisation of empirical ensemble refinement parameters (τx, pTLS and Tbath). Simulations are performed independently and in parallel. The plot …

https://doi.org/10.7554/eLife.00311.004

Ensemble refinement parameters and results as function of resolution of the datasets. (A) Gain in Rfree of ensemble refinement compared with re-refinement using phenix.refine, (B) number of …

https://doi.org/10.7554/eLife.00311.005

Validation of ensemble refinement using dataset 1YTT with exceptionally high quality experimental phases. (A) Real space cross-correlation of experimentally phased electron density map (|Fobs|exp[o…

https://doi.org/10.7554/eLife.00311.009

Sampling reproducibility of ensemble refinement. (A) Cross-correlations (CC) calculated for all pairs from 10 random-number seed repeat ensemble refinements of the 1UOY dataset extending to 1.5-Å …

https://doi.org/10.7554/eLife.00311.010

Reproducibility of side-chain rotamer distributions. Mean χ1 and χ2 distributions of four side-chains from the 10 repeats, with error bars ±1 σ, are shown for 1UOY. The four residues presented are …

https://doi.org/10.7554/eLife.00311.011

Ramachandran analysis. Distribution of Ramachandran torsion angles classified as outliers (red) and allowed (blue) for ensemble models, 1UOY (A) and 1BV1 (B). Plot shows percentage of classification …

https://doi.org/10.7554/eLife.00311.012
Figure 6—source data 1

Geometries of single-structure models and ensemble models.

Rms deviations (RMSD) from ideal bond, angle and dihedral geometries calculated for single structures re-refined using phenix.refine. Geometries for ensemble structures were calculated using two methods, the ‘whole distribution’, where the RMSD was calculated for each restraint (averaged over all structures), √〈(xidealxmodel)2〉, and ‘centroid’ where the RMSD was calculated using the mean deviation from ideality for each restraint, √〈(〈xidealxmodel〉)2〉, which for unimodal functions equals √〈(xideal − 〈xmodel〉)2〉.

https://doi.org/10.7554/eLife.00311.013
Figure 6—source data 2

Ramachandran statistics for re-refined and ensemble models.

The Ramachandran statistics for the ensemble models are calculated in two ways: ‘Ramachandran (mean)’ shows the percentage of outliers, allowed and favoured averaged over all structures in the ensemble (cf. ‘whole distribution’ in Figure 6—source data 1), whereas ‘Ramachandran (mode)’ shows these percentages based on the most frequent occurring classification of each φ,ψ combination (cf. ‘centroid distribution’ in Figure 6—source data 1).

https://doi.org/10.7554/eLife.00311.014
Figure 7 with 4 supplements

Comparison of atomic fluctuations for non-crystallographic symmetry related protein copies for dataset 1M52. (A) Cα trace of the re-refined single structure coloured by B-factor (from blue to red …

https://doi.org/10.7554/eLife.00311.015
Figure 7—figure supplement 1

Comparison of atomic fluctuations for NCS related protein copies for dataset 2R8Q.

https://doi.org/10.7554/eLife.00311.016
Figure 7—figure supplement 2

Comparison of atomic fluctuations for NCS related protein copies for dataset 1YTT.

https://doi.org/10.7554/eLife.00311.017
Figure 7—figure supplement 3

Comparison of atomic fluctuations for NCS related protein copies for dataset 1IEP.

https://doi.org/10.7554/eLife.00311.018
Figure 7—figure supplement 4

Comparison of atomic fluctuations for NCS related protein copies for dataset 2XFA.

https://doi.org/10.7554/eLife.00311.019

Ensemble refinement of two isomorphous proline isomerase datasets collected at 100 K and 288 K. (A) Left, basal TLS B-factors of ensemble models for 100 K and 288 K datasets (blue and green, …

https://doi.org/10.7554/eLife.00311.020

Overview of side-chain dynamics in ensemble structures. Atoms are coloured by their relative probability in the ensemble (see ‘Materials and methods’), reflecting the degree of disorder (ranging …

https://doi.org/10.7554/eLife.00311.021

Dynamics in the binding pocket of proline isomerase at 288 K. (A) The location of the binding pocket comprised of residues Arg55, Met61, Ser99 and Phe113. (B) Zoom in of binding pocket (as dotted …

https://doi.org/10.7554/eLife.00311.022

Comparison of ensemble structures of bound and unbound forms of HIV protease. (A) Residues in the P1 binding sites are disordered in the unbound HIV protease (2PC0), left-hand side, with carbon …

https://doi.org/10.7554/eLife.00311.023

ABL-kinase Imatinib binding site. (A) Imatinib binding site in chain A of the 1IEP dataset showing distribution of the six protein–ligand hydrogen bonds in chain A and chain B (red and blue …

https://doi.org/10.7554/eLife.00311.024

Correlation of R-values and overall map correlation coefficient for the 1YTT dataset in the block selection procedure. The correlation coefficients are calculated between the experimentally phased …

https://doi.org/10.7554/eLife.00311.026

Interpretation of global and local details of 1UOY ensemble model is aided by relative atomic probability (as described in ‘Materials and methods’). Ensemble models, left and centre, are colour by …

https://doi.org/10.7554/eLife.00311.027

Tables

Table 1

Ensemble refinement statistics for 20 datasets. Datasets were taken from the PDB or PDB_REDO and were re-refined using ensemble refinement and phenix.refine. The relaxation time τx used, the …

https://doi.org/10.7554/eLife.00311.003
PDB IDResolution (Å)Ensemble refinementphenix.refineEnsemble—phenix.refine
τx (ps)No. of structuresRworkRfreeRworkRfreeΔRworkΔRfree
1KZK1.11.56000.1250.1530.1360.155−0.011−0.003
3K0M1.32.02500.1040.1290.1160.132−0.012−0.003
3K0N1.41.02090.1150.1330.1190.143−0.004−0.010
2PC01.40.82500.1450.1880.1610.193−0.016−0.005
1UOY1.51.01670.1040.1370.1550.185−0.051−0.049
3CA71.50.8400.1490.1840.1710.212−0.022−0.029
2R8Q1.51.02000.1320.1620.1580.178−0.026−0.016
3QL01.60.5700.2040.2540.2290.270−0.024−0.017
1X6P1.61.04000.1210.1490.1400.175−0.019−0.026
1F2F1.70.81430.1280.1680.1600.198−0.032−0.031
3QL31.80.5800.1600.2080.1700.221−0.010−0.013
1YTT1.80.3840.1390.1740.1660.189−0.027−0.014
3GWH2.01.0390.1600.2000.1870.220−0.027−0.021
1BV12.00.4780.1490.1820.1540.205−0.005−0.023
1IEP2.10.52000.1830.2380.1960.245−0.012−0.007
2XFA2.11.01000.1710.2170.1840.244−0.013−0.027
3ODU2.50.3500.2080.2690.2190.281−0.010−0.012
1M522.60.5500.1610.2110.1680.228−0.007−0.017
3CM82.90.5670.1940.2350.2050.248−0.011−0.013
3RZE3.10.1720.2100.2800.2100.2910.000−0.011
Max−0.051−0.049
Min0.000−0.003
Mean−0.018−0.018
Table 2

Rms (mFobsDFmodel)exp[model] difference densities obtained from ensemble refinement and re-refinement in phenix.refine

https://doi.org/10.7554/eLife.00311.006
PDB IDResolution (Å)σmFo−DFc (e/Å3)
Ensemblephenix.refine
1KZK1.10.1380.161
3K0M1.30.0160.018
3K0N1.40.0070.008
2PCO1.40.0990.099
1UOY1.50.1150.162
3CA71.50.1320.148
2R8Q1.50.1040.118
3QL01.60.1240.138
1X6P1.60.0980.105
1F2F1.70.1040.126
3QL31.80.1310.139
1YTT1.80.1700.215
3GWH2.00.1250.138
1BV12.00.1090.119
1IEP2.10.0840.091
2XFA2.10.0690.074
3ODU2.50.1050.113
1M522.60.0880.093
3CM82.90.0360.036
3RZE3.10.0700.070
Table 3

Effect of input structure on ensemble refinement. For three datasets ensemble refinement was performed using a starting structure from three different refinement programs. For each structure three …

https://doi.org/10.7554/eLife.00311.007
PDBRe-refinementEnsemble refinement
Repeat 1Repeat 2Repeat 3Mean
ProgramRworkRfreeRworkRfreeRworkRfreeRworkRfreeRworkRfree
1UOYBuster0.1670.1960.1080.1440.1120.1450.1100.1460.1100.145
Refmac0.1470.1700.1040.1370.1030.1400.1050.1440.1040.140
Phenix0.1550.1850.1090.1420.1090.1470.1110.1490.1100.146
3CA7Buster0.1770.2080.1370.1860.1370.1920.1410.1970.1380.192
Refmac0.1700.2050.1390.1870.1350.1890.1380.1930.1370.189
Phenix0.1710.2120.1380.1800.1420.1890.1480.1930.1420.187
1BV1Buster0.1610.2040.1370.1840.1380.1850.1370.1860.1380.185
Refmac0.1780.2310.1400.1820.1430.1840.1430.1890.1420.185
Phenix0.1540.2050.1390.1880.1380.1890.1400.1890.1390.189
Table 4

Fmodel cross-correlation scores for ensembles generated with different input models. Three different refinement programs generated alternative starting structures, see Table 3. The best ensemble was …

https://doi.org/10.7554/eLife.00311.008
PDBEnsemble pairCC
Re-refined inputRe-refined input
1UOYRefmacBuster0.997
RefmacPhenix0.997
BusterPhenix0.999
3CA7RefmacBuster0.993
RefmacPhenix0.992
BusterPhenix0.996
1BV1RefmacBuster0.992
RefmacPhenix0.990
BusterPhenix0.992
Table 5

Comparison of three B-factor models for ensemble refinement. Burling et al. (Burling and Brunger, 1994) had shown previously that the choice of ADPs for ensemble refinement can affect the resultant …

https://doi.org/10.7554/eLife.00311.025
PDBResolution (Å)Global isotropic B-factorRefined ADPsFitted TLS ADPs
RworkRfreeWilson B-factor (Å2)Global B-factor (Å2)RworkRfreeScale factorRworkRfreepTLS
3K0M1.30.1170.14712.012.00.1250.1460.90.1030.1300.3
3K0N1.40.1210.15319.119.10.1260.1530.90.1140.1330.1
1UOY1.50.1030.14810.49.40.1070.1440.90.1010.1360.3
3CA71.50.1290.19416.813.40.1420.1920.90.1420.1900.5
1X6P1.60.1080.15815.912.70.1130.1520.80.1210.1500.8
1F2F1.70.1160.18415.614.80.1230.1670.80.1260.1670.7
1BV12.00.1250.19222.618.10.1350.1910.80.1450.1820.6
Mean-0.1170.168--0.1250.164-0.1220.155-

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