Table I. Structural features of the benchmark proteins.

PDB I.D.	Protein name	Number of chains	Homologous chains	Number of residues in chains	Total residue	Resolution (Å)	Structural type	SCOP class
2e86	Copper-containing nitrite reductase trimer	3	3	3 × 337	1011	1.50	Symmetric, homocomplex	All β proteins
1eer	Erythropoietin complexed with its receptor	3	2	2 × 227	620	1.90	Asymmetric, heterocomplex	All β proteins
			+1	+166				All α proteins
1gp2	G protein heterotrimer: Gi α 1–β 1–γ 2	3	1	353	764	2.30	Asymmetric, heterocomplex	α and β
			+1	+340				Proteins (a/b)
			+1	+71				All β proteins
								All α proteins
1ado	Aldolase tetramer	4	4	4 × 363	1452	1.90	Asymmetric, homocomplex	α and β
								Proteins (a/b)
1z0k	Rab GTPase complexed with rabenosyn-5	4	2	2 × 172	482	1.92	Asymmetric, heterocomplex	α and β
			+2	+2 × 69				Proteins (a/b)
								All α proteins
1akj	MHC class I glycoprotein HLA-A2 with T-cell coreceptor CD8	4	1	276	615	2.65	Asymmetric, heterocomplex	All β proteins
			+1	+99				α and β
			+2	+2 × 120				Proteins (a+b)
1b0c	Pancreatic trypsin inhibitor	5	5	5 × 58	290	2.80	Symmetric, homocomplex	Small proteins
1wnr	10-kDa chaperonin	7	7	7 × 94	658	2.90	Symmetric, homocomplex	All β proteins