The Alber lab at UC Berkeley is pleased to release of the code for Ringer version 1.0 (http://ucxray.berkeley.edu/ringer.htm), which depends on Chimera. Ringer is a program to detect molecular motions by systematic X-ray electron-density sampling. The aim of Ringer is to go beyond static structural snapshots of proteins by uncovering structural ensembles in X-ray electron density. This information can reveal not only which parts of proteins are flexible and which parts are rigid, but it also can define alternate conformations that may be important for function. Alternate conformations of binding sites also may afford additional targets for drug design. The Ringer method is described in Lang et al. /Protein Sci/. 2010 Jul; 19(7):1420-31 <http://www.ncbi.nlm.nih.gov/pubmed/20499387>. An application of Ringer, determining the structural underpinnings of the side chain dynamics critical for the function of the enzyme proline isomerase, was published in Fraser JS et al. /Nature/. 2009 Dec 3;462(7273):669-73 <http://www.ncbi.nlm.nih.gov/pubmed/19956261>. Ringer is freely available to academics. -- PaulaTherese Lang Postdoctoral Scholar Alber Lab, UC Berkeley http://ucxray.berkeley.edu/ringer.htm