AUTO-XPL - A UNIX SHELI-SCRIPT SYSTEM TO SEQUENCE X-PLOR REFINEMENT RUNS

A Unix shell script has been written to automate many of the individua l computational steps involved in refining the crystal structure of a biopolymer using Axel Brunger's program X-PLOR. The script controls th e sequential execution of different refinement operations, automatical ly piping the output from each operation into the input for the next o peration. The performance of each individual operation is monitored in terms of the progression of the free R factor and the step is repeate d with a smaller number of minimization cycles if necessary in order t o achieve the lowest observed free R factor. Most refinement parameter s can be adjusted or reset for each individual step, allowing long seq uences of refinement operations to be executed without manual interven tion. The script can also be used to automate the evaluation of the ef fect of variations in input-parameter values on the performance of a r efinement procedure.