Table 1.

Optimal cross-linker length for three proteins of varying size, with Δ at 3, 6, and 12

				Optimal cross-linker length Δ
Protein	No. of residues	No. of lysines	No. of models	3	6	12
FGF-2	146	14	13	9 Å	12 Å	12 Å
Deoxyribonucleoside kinase	230	13	85	15 Å	14 Å	15 Å
α-Catenin	269	14	50	15 Å	14 Å	20 Å

Among the five commercially available cross-linkers, we predict that three of them, DMP (9.2 Å), BS³ (11.4 Å), and sulfo-EGS (16.1 Å), would be variously optimal for these models.