Critical assessment of methods of protein structure prediction - Round VIII.

This article is an introduction to the special issue of the journal Proteins, dedicated to the eighth CASP experiment to assess the state of the art in protein structure prediction. The article describes the conduct of the experiment, the categories of prediction included, and outlines the evaluation and assessment procedures. Highlights are the first blind assessment of model refinement methods showing that under some circumstances substantial model improvements are possible; improvements in the performance of methods for determining the accuracy of a model; and some progress in the accuracy of comparative models in regions not present in a principal template. Against these advances must be stacked the fact that there is no detectable progress in model quality compared with CASP7 in either template-based or template free modeling, using the established CASP measures.