Table 3. Average minimum heavy-atom distance between “gatekeeper” residues in the channel of Hs-MIF, Gl-MIF, Pf-MIF, Pb-MIF, and Py-MIF.

Protein	PDB-ID	Residue 44 (X, Å)	Residue 100 (X, Å)
Gl-MIF	3T5S	N, 5.5	R, 3.9
Hs-MIF	1MIF	Y, 5.3	V, 6.7
Pf-MIF	2WKF	R, 3.6	D, 4.6
Pb-MIF	2WKB	R, 5.8*	D, 4.9
Py-MIF	3GAD	R, 3.8	D, 4.3

^*One of the three arginine side chains in the trimer is “flipped” such that there is no three-fold symmetry between the three arginines. Consequently, the “hole” is larger at this site in Pb-MIF