Table 1.

Comparison of reactive loop sequences of wild-type and variant crmAs with antithrombin

	P4	P3	P2	P1	P1′	P2′	P3′	P4′
Wild-type crmA	L	V	A	D	C ↓	A	S	T
P1R crmA	L	V	A	R ↓	C ↓	A	S	T
P1G P1′R crmA	L	V	A	G	R ↓	A	S	T
Antithrombin	I	A	G	R ↓	S	L	N	P

Reactive loop amino acids are designated by the single-letter code and numbered P1, P2, P3, etc., from the N-terminal side and P1′, P2′, P3′, etc., from the C-terminal side of the P1–P1′ reactive bond based on standard nomenclature. Principal cleavage sites of thrombin, factor Xa, and trypsin are designated by bold arrows and of elastase by unbolded arrows.