Table 2.

Sequence comparison based on S.EcoA0ORF42P

HsdS subunit	Per cent identity in regionsa					Recognition siteb
	N-cons	TRD1	Central cons	TRD2	C-cons
S.EcoEI	80	26	86	72	83	GAGN(7)ATGC
S.EcoO157ORF5947P	91	30	89	21	84
S.EcoKO157ORF5307P	91	30	89	21	84
S.EcoAI	88	26	86	16	76	GAGN(7)GTCA
S.EcoCFTORF5424P	88	26	85	16	76
S.CfrAI	85	27	85	24	84	GCAN(8)GTGG
S.StySKI	83	29	85	23	76	CGATN(7)GTTA

^a The numbers reflect the per cent identity in each of the regions recalculated on the basis of the alignments given by BLAST in REBASE [1] for the entire sequence of S.EcoA0ORF42P. The conserved (cons) and variable (TRD = target recognition domain) regions for Type IB are defined according to Kannan et al. [17]. ^b Only known recognition sequences are shown.