Table 4.

Residues at positions homologous to active site residues of human serotransferrin.

	Site1	Clade2
	Iron-binding	S	L	ICA	O	M	M-like
N-lobe	63	D	D,G	D,G	D,G	D,F,N,S	D
	95	Y	Y	Y,H	Y	Y	I,T,V
	188	Y	Y	Y,S	Y	Y,G	N,S
	249	H	H,N	H	H	H,R	G,K,R
C-lobe	392	D	D,G	D	D	D,G,K,R,S	D
	426	Y	Y	Y,H	Y	Y,H	A,L,V
	517	Y	Y	F,P,S	Y	Y,D	N
	585	H	H	H,R	H	H,Q,R	N,S
	Carbonate-binding
N-lobe	124	R	R,W	R,C,W	R,K	R,Q	W3
C-lobe	456	R	R	T3	R	R,M,S	S3
Mean amino acid diversity (%)4,5		0.0%	5.0% *	29.3% **	2.4%	30.1% **	28.4% *
No. conserved residues shared with S		10	6	2	8	1	2

¹Sites numbered as in human serotransferrin (NP_001054).

²As in Figure 2.

³Clade-specific conserved residue.

⁴Amino acid diversity at the 10 active site residues.

⁵Paired t-tests of the hypothesis that mean amino acid diversity equals that for S:

^*P < 0.05;

^**P < 0.01.