TABLE 1.

The Identified XLs for individual components of pairwise protein–protein interactions with previously solved structures.

Components	Reference PDB	# K–K PAIRS	# INTRA-XLS	# INTER-XLS
C3B	2WII (X-ray, 2.7 Å)	5,886	43	–
C5B	4A5W (X-ray, 3.5 Å)	6,105	32	–
C5B–C6	6H04 (EM, 5.6 Å)	6,882	–	5
C6–C7	6H04 (EM, 5.6 Å)	2,728	–	8
C7–C8 (α, β, and γ)	6H04 (EM, 5.6 Å)	2,640	–	16
C8 (α, β, and γ)	3OJY (X-ray, 2.51 Å), 6H04 (EM, 5.6 Å)	1,031	10	–
C8 (α, β, and γ)–C9	3OJY-6DLW (EM, 3.9 Å)	2,040	–	5
C9–C9	6H04 (EM, 5.6 Å)	561	3	4

The individual components analyzed, the reference PDB (method, resolution), number of intra-XLs (threshold < 32 Å), and number of inter-XLs (threshold < 32 Å) are shown in the table columns, respectively. For C9–C9 interaction, detected XLs that could not be explained on a single C9 protein (above threshold), but in C9–C9, were considered as inter-XLs.