by test on Sat Sep 06, 2008 9:23 am
Well, the definition of TBM and FM are subjective instead of objective. How to implement what you suggested without introducing too much artificial bias?
In addition, GDT-TL may be too strict and is likely to bury some subtle difference.
In the CASP7, to assess the quality of C_alpha trace, GDT-HA was used for both TBM and HA-TBM targets.
I would like to see the CASP8 assessors to use a even higher-accuracy measure such as GDT-TL (0.25, 0.5 1.0 2.0)
especially for HA-TBM tagets as done in the CAST6. Nowadays, protein model quality is improving steadily
especially for TBM targets, and CASP should ask/encourage predictors to devise more accurate modeling
globally (for FM targets) as well as locally (for TBM targets). I feel like 8A is too large a distance to be
meaningful even for FM targets (however, 8A gives us a complacent feeling of good protein modeling)
On the other hand, for the calculation of GDT scores, only positions of C_alpha atoms matter.
Since there are many more non-C_alpha atoms in protein models (CASP8 did not accept C_alpha only models),
CASP8 assessors should consider to include additional measures other than the HB score used in the CASP7.
Candidate measures include Chi_1 and Chi_12 for all/TBM targets.
One should also consider to use the HB score for all targets not restricted to TBM.
Just a thought....