Residue IE Score: Monitors that all PHE, TYR, and TRP residues are scoring well.
Core Existence: Ensures that at least 25% of the residues are buried in the core of your design.
Fragment Score: Scans for parts of your design that are unlikely to fold up naturally. Use Rebuild and Remix tools to fix these regions of your design!
Secondary Structure: Checks that at least 25% of residues are in sheets; penalties are incurred if fewer than 25% of residues form sheets.
Secondary Structure Design: Penalizes GLY residues in helices and sheets.
How does the Secondary Structure Design know if a glycine is in a sheet or helix?
The DSSP filter checks to see if a segment has (ideally) two hbonds to another distant segment (antiparallel sheet) or two adjacent segments (parallel sheets) or to the segment exactly 4 upstream (helix). It probably also has some smoothing, like making sure the bonding pattern continues for at least 2 or 3 segments in a row. I don't think the DSSP algorithm looks at angles at all, but it might do that to supplement the bonding information.
brow42 is correct. The Secondary Structure filter and the Secondary Structure Design filter both use the DSSP algorithm. DSSP defines helices and sheets based on hydrogen bonding patterns alone.*
(*I believe DSSP can use bond angles to discern certain types of loops, but this is not used in Foldit.)
It would have been nice enable it. Without add/delete you have to start from zero if you want to change a bit your design
This was an oversight on our part. We'll make sure players can insert/delete segments next time!