Table 2.

Clusters and sequence motifs.

Structure-based clustering only
Hydrogen bonding clustering			Torsion angle clustering
clusters	% cov by motif	% cov by significant motif	clusters	% cov by motif	% cov by significant motif
2597	6	0.4	1747	9.7	3.6
Structure-based and sequence-based clustering
Hydrogen bonding clustering			Torsion angle clustering
clusters	% cov by motif	% cov by significant motif	clusters	% cov by motif	% cov by significant motif
7170	54.2	30.0	8866	39.1	17.1

Percentage of structural classes covered by sequence patterns. The first column shows the number of classes obtained for the hydrogen bond-based clustering before and after the sequence-clustering step. The second column shows the percentage of clusters for which a sequence pattern could be derived by using the Pratt program before and after the sequence-clustering step. The third column shows the percentage of classes that could be assigned to a statistically significant motif before and after the sequence-clustering step. Colums four, five and six show the same numbers for the backbone torsion angle-based clustering.