Table 3. Performance of models based on direct feature combination for the bound sequence dataset, evaluated by LOOCV.

Feature	F	SN	SP	ACC	AUC
A	0.311	0.671	0.675	0.680	0.678
A+B	0.313	0.670	0.685	0.689	0.676
A+B+C	0.311	0.662	0.678	0.685	0.680
A+B+C+D	0.309	0.608	0.723	0.719	0.680
A+B+C+D+E	0.312	0.650	0.695	0.698	0.676
A+B+C+D+E+F	0.309	0.637	0.713	0.711	0.677
A+B+C+D+E+F+G	0.307	0.681	0.658	0.669	0.669

A: evolutionary profiles; B: predicted relative accessible surface area; C: physicochemical propensities; D: sparse profile; E: function composition; F: predicted secondary structure; G: amino acid pair.