Columns from BUSTER (refine.mtz)

A BUSTER output MTZ file (usually named refine.mtz) generally contains twenty-four columns:

Column names Origin Description Scale
H,K,L Reflection indices. N/A
FP,SIGFP (or similar) input Observed data (amplitude and sigma). The column names will be identical to the column names of the input data. Observational (unmodified from input).
FreeR_flag (or similar) input Flag indicating which reflections are in the free set. Copied from input if present, otherwise created afresh. N/A
FC,PHIC BUSTER Calculated structure factors (amplitude and phase) for the complete model, containing atomic model, bulk-solvent and (if specified) the missing atom model. Absolute
2FOFCWT,PH2FOFCWT BUSTER Coefficients for the electron-density map defined as 2*m*Fo-D*Fc*. Absolute
FOFCWT,PHFOFCWT BUSTER Coefficients for the electron-density difference map defined as m*Fo-D*Fc. Absolute
FOM BUSTER Figure of merit: m. N/A
HLA,HLB,HLC,HLD BUSTER Hendrickson-Lattman coefficients of the BUSTER phase probability distribution. N/A
FCTR,PHICTR BUSTER Coefficients for the centroid electron density map. Absolute
FOFRGSLV,PHFOFRGSLV BUSTER Coefficients for the electron-density map defined as 2*m*Fo-D*Fc without the contribution of the missing atom model to FC. Usually there is no missing atom model defined for a BUSTER refinement, in which case these columns will be identical to the FOFCWT,PHFOFCWT columns. Absolute
FOSC,SIGFOSC BUSTER Observed data (see FP,SIGFP above) scaled to FC. Absolute
FX BUSTER Expectation of the amplitude of the complex-valued model structure factor. Absolute

Using BUSTER MTZ file in Coot

For visualising the typical set of maps (2Fo-Fc and difference map), eg. Coot could be started with

% coot --pdb refine.pdb --auto refine.mtz

and it will pick the correct columns (2FOFCWT/PH2FOFCWT and FOFCWT/PHFOFCWT) automatically.

Comparing column names for different refinement programs

To simplify switching between refinement programs (or following documentation written for one refinement program), here are some column names compared. Please note that some programs allow the user to use any name they want for the output columns - we are only listing the default names in the table below.

Explanation BUSTER REFMAC Remark
2Fo-Fc map coefficients 2FOFCWT PH2FOFCWT FWT PHWT
Fo-Fc (difference map) coefficients FOFCWT PHFOFCWT DELFWT PHDELWT
Figure of merit FOM FOM
Model structure factor FC PHIC FC_ALL PHIC_ALL Atomic and bulk-solvent model; BUSTER will also contain the contribution from the (optionally declared ) missing atoms.