ABS (CCP4: Supported Program)

NAME

abs - A program to determine the absolute configuration (hand) of the heavy atom substructure and calculate an FOM.

SYNOPSIS

abs hklin foo_in.mtz
[Key-worded input]

DESCRIPTION

ABS is a program to determine the absolute configuration (hand) of the heavy atom substructure or polar space group using anomalous scattering. It also calculates a figure of merit which is a useful assessment of the heavy atom substructure. The algorithm is based on the Ps function method (Woolfson & Yao, 1994 and Hao & Woolfson, 1989).

INPUT AND OUTPUT FILES

Input

HKLIN: (compulsary); Input MTZ file. This should contain the conventional (CCP4) asymmetric unit of data (preferably from TRUNCATE). See the LABIN keyword for columns used.

Output

Results are shown in the log file.

KEYWORDED INPUT

The various data control lines are identified by keywords. Only the first 4 characters of a keyword are significant. The cards can be in any order. Numbers in [ ] are optional and can be left out. The available keywords are:

TITLE, LABIN, RESOLUTION, ATOM

TITLE <title string>

Upto 80 character title.

LABIN F=... SIGF=... DANO=... SIGDANO=...

(Compulsory.)
F: mean F magnitude.
SIGF: standard deviation of F.
DANO: Friedel difference. Must be column type D.
SIGDANO: standard deviation of F2.

RESOLUTION <rmin>

High resolution cutoff in Angstrom (default value = 4).

ATOM <x> <y> <z> [<occupancy>]

(compulsory)
Fractional coordinates of anomalous scatterer(s).

PRINTER OUTPUT

Results are shown in the log file.

EXAMPLES

Non-runnable examples

abs hklin /ccpdisk/xtal/ccp4/new_programs_4.2/hao_/ompdc.mtz <<eof
TITLE determination of absolute configuration
RESO 3.0
ATOM   0.88364   0.45255   0.20904
ATOM   0.78647   0.72103   0.20167
ATOM   0.84051   0.61635   0.11817
ATOM   0.72479   0.61860   0.11258
ATOM   0.72077   0.55255   0.14145
ATOM   0.59536   0.59265   0.24685
ATOM   0.86602   0.58829   0.40655
ATOM   0.77843   0.69468   0.11515
ATOM   0.75302   0.81095   0.19786
ATOM   0.69114   0.73137   0.22579
ATOM   0.61948   0.76388   0.20633
ATOM   0.54273   0.63876   0.12769
ATOM   0.63899   0.79544  -0.08076
ATOM   0.48613   0.55253   0.55323
ATOM   0.61479   0.44768   0.54001
ATOM   0.55872   0.43179   0.61568
ATOM   0.62674   0.45720   0.64670
ATOM   0.53478   0.56807   0.73165
ATOM   0.66755   0.78155   0.57921
LABIN F=F2 SIGF=SIGF2 DANO=DANO2 SIGDANO=SIGDANO2
eof

REFERENCES

Hao, Q. (2001), in preparation.

AUTHORS

Q. Hao

MacCHESS, Wilson Synchrotron Lab, Cornell University, NY 14850, USA

Email: qh22@cornell.edu