Table 2. Input structures and accessory data.

PDB	Chains	Res. (Å)	Dimer type	SASA (Å2)	Anchor	Chain	Loop	Loop length
1dle	A/B	2.1	crystal dimer**	2,800	38	B	36–40***	8
1fc4	A/B	2	homodimer	10,000	74	B	69–79	11
1qni	A/B	2.4	homodimer	11,800	408	B	397–411	15
2qpv	A/B	2.35	homodimer	2,900	55	B	50–57	8
3dxv	A/B	2.21	homodimer	7,900	291	B	288–299	12
1u6e	A/B	1.85	homodimer	6,700	86	B	80–89	10
2bwn	A/B	2.1	homodimer	8,500	85	B	77–90	14
1jtp	M/B	1.9	heterodimer	1,600	104	B	99–108	10
2hp2	A/B	2.7	homodimer	9,500	2306	B	2294–2309	16
2wya	B/C	1.7	homodimer	5,900	1009	C	1003–1012	10
2obg	A*	2.35	heterodimer	1,600	1080	A	1077–1086	10
2i25	M/O	1.8	heterodimer	1,400	91	O	86–93	8
3cgc	A/B	2.3	homodimer	5,400	429	B	421–434	14
3ean	A/B	2.75	homodimer	7,900	473	B	467–474	8
1fec	A/B	1.7	homodimer	6,400	459	B	456–463	8
1zr0	A/B	1.8	heterodimer	1,400	15	B	10–17	8

This table collects structural parameters for the complexes used in this work, along with chosen parameters like anchor placement. The PDB column identifies the structure. The chains column identifies which complex within the PDB file was used (several have many complexes in the asymmetric unit). *: 2obg was not crystallized as a heterodimer; it was expressed as a fusion protein and crystallized as an infinitely domain-swapped polymer.[24] The resolution column contains the reported crystal structure resolution; all are reasonable. The dimer type column identifies the type of dimer. **: 1dle represents a crystal dimer rather than a biological one, making it a good test of weak interactions. The SASA column notes the area buried by the interface. The anchor and chain columns together identify the residue used as an anchor. The loop column identifies which residues (on the same chain as the anchor) were flexible. The loop length column collects the lengths of these loops. ***: 1dle has residues with insertion codes in the loops, leading to a longer loop than is obvious. The name column identifies the name and function of the protein as listed in the PDB.