The lists were generated using a local version of an algorithm similar to that employed by pisces.

For SA-search, compared to other protein list generators, we use more stringent criteria to select the proteins.
In particular we exclude chains missing atoms, alternate conformations on the backbone, a condition to obtain a correct encoding of structures using HMM-SA. Chains having breask are split in several independent fragments noted as 5csmA_1, 5csmA_2i for instance.
Proteins determined at a too low resolution are also discarded (more than 2.5 Angströms).

Since 2006, we do not use separate lists for X-Ray and NMR structures.
You can access the current lists here:

RX&RMN-30 (5986 protein chains or fragments)
RX&RMN-50 (8992 protein chains or fragments)
RX&RMN80 (12010 protein chains or fragments)

Having defined lists of non redundant proteins, we build banks of HMM-SA encoded structures.
  
The current lists were built June  2006.
Note: the culling service is still under construction.