Introduction

The Automated Refinement Procedure, ARP/wARP , is a program package for protein structure refinement. It combines in an iterative manner the reciprocal space structure factor refinement with updating of the model in real space. The latter attempts to mimic and automise a typically time extensive model rebuilding session at the graphics. The real space update is based on identifying and removing poorly defined atoms and the addition of potential new sites. This utilises some general shape properties of the electron density syntheses as well as stereo-chemical criteria.

The ARP/wARP suite is under continuous development. The present release, Version 5.0, can be used in the following ways:

1.

Refinement of MR solutions

2.

Improvement of MAD and M(S)IR(AS) phases

3.

Averaging of multiple refinements

4.

Automatic tracing of the density map and model building ($\alpha$-version)

5.

Building of the solvent structure

6.

Ab initio structure determination for metalloproteins at very high resolution

For a more detailed description of the ARP see ARP93 and the other references given at the end of the document.