Introduction

The Automated Refinement Procedure, ARP/wARP $\!\!,$  is a program package for protein structure refinement. It combines in an iterative manner reciprocal space structure factor refinement with updating of the model in real space. The latter attempts to mimic and automate a typically time extensive model rebuilding session at the graphics. The real space update utilises some general properties of the electron density synthesis as well as stereo-chemical criteria.
The ARP/wARP suite is under continuous development. The present release, Version 5.1, can be used in the following ways:

1.

Automatic tracing of the density map and model building

2.

Refinement of MR solutions

3.

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

4.

Averaging of multiple refinements

5.

Building of the solvent structure

6.

Ab initio structure determination for metalloproteins at very high resolution

For a more detailed description of ARP/wARP  see [1] and the other references given at the end of the document.