Table 3.

Lower threshold of SVM scores for defining 'unknown' category of similarity relations between domains

SCOP class	SCOP fold(s)	SVM score at 5% percentile
α/β	Rossmann-like folds (77 SCOP folds)	-0.8
α + β	Ferredoxin-like	-1.0
All α	Four-helical up-and-down bundle	0.4
All β	OB-fold	-1.1
Average		-0.6

The average value in the table is the determined lower boundary for the distributions of scores between folds that share local similarity but are not global structure templates for each other (false positives).