Table 1. FcRn and IgG residues known to be involved in FcRn–IgG interaction.

α-chain residue	Human	Rabbit	Fc residue	Human IgG				Rabbit IgG
				1	2	3	4
115	E	E	310	H	H	H	H	H
116	E	D	311	Q	Q	Q	Q	Q
130	D	E	435	H	H	R	H	H
131	W	W	253	I	I	I	I	I
135	L	L	436	Y	Y	F	Y	Y
β2m residue
1	I	V	307	T	T	T	T	P
2	Q	Q	288	K	K	K	K	R

Numbering is based on the hFcRn, hβ2m and the hIgG1 sequences, respectively.