Table 1.

Comparison between the sequence conservation of the SSE classes (quantified by average information content) and the position of the substrate recognition sites from references^17,18.

SSE label	Residue range (in 2nnj)	Heme	Average information content	Gotoh 1992	Zawaira et al. 2011
K″	409–412		2.18
β1-5	96–97	✓	2.06
β6-1	362		1.98
K	346–359	✓	1.98	SRS 5	SRS 5
β6-2	477		1.87
β3-1	164		1.84
L′	464–466		1.77
L	438–455	✓	1.76
J	317–331		1.76
K′	391–396		1.70
J′	339–345		1.67
C	117–131		1.67		SRS 1
β5-1	274		1.61
β1-4	368–369	✓	1.60	SRS 5	SRS 5
β3-3	456–459		1.55
β2-1	374–376		1.55
I	284–316	✓	1.54	SRS 4	SRS 4
β5-2	280		1.53
β1-2	72–77		1.51		SRS 1'b
β2-2	379–381		1.49
G′	220–226		1.47		SRS 2
B	80–90		1.43
β3-2	485–489		1.41
F′	211–219		1.38		SRS 2
H	263–274		1.37
β1-3	386–389		1.35
β1-1	64–69		1.31		SRS 1'b
E	166–183		1.22
β1-0	32		1.20
D	141–159		1.20
B″	112–114	✓	1.20
β4-2	478–479		1.18		SRS 6
A′	42–44		1.18		SRS 1'a
A	50–61		1.12
G	227–254		1.04	SRS 3	SRS 3
F	192–209		0.86	SRS 2	SRS 2
B′	101–107	✓	0.73	SRS 1	SRS 1
β4-1	473–474		0.70	SRS 6	SRS 6

The SSEs are sorted from the most conserved to the most variable. The “Heme” column marks the SSEs with any atom within 8 Å from the heme cofactor.