2.1 | Scope of the experiment
In the Spring and Summer of 2022, CASP solicited 103 yet-to-be-published
structures as potential modeling targets for the CASP15 experiment. The
structures were provided by 48 structure determination groups from 14
countries all over the world. They include single-sequence protein
molecules, protein-protein complexes, RNA molecules, RNA-protein
complexes, and protein-ligand complexes. Ninety-eight proposed targets
were deemed suitable for the CASP experiment and were gradually released
for prediction over a period of three months (May 2 through July 29,
2022). Together with target sequences, predictors were provided the
information on the oligomerization state of the targets and availability
of bound organic ligands or ions (17). All in all, CASP15 offered 47
multimeric protein complexes for modeling in the Protein assembly
category (40 assessed), 81 monomeric proteins or subunits of multimeric
complexes in the Tertiary Structure category (77 assessed, divided into
112 Evaluation units (18)), 12 RNA structures in the RNA category, 23
protein-ligand complexes in the Ligand binding category, and two
protein-RNA complexes. 89 research labs from 17 countries submitted
models in one or more categories, with the USA (30 labs) and China (29
labs) most represented. Some labs created more than one participating
group, so that 162 groups were assessed altogether. Of these, 56 are
server groups, where target sequences are sent directly to a
CASP-registered computer and a response is required within 72 hours. For
non-server groups, usually there was a three-week window in which to
submit models, allowing time for human intervention.