Table 1. Subtypes of Type II REases.
| Subtypea | Defining feature | Examples | Recognition sequence |
|---|---|---|---|
| A | Asymmetric recognition sequence | FokI | GGATG (9/13) |
| AciI | CCGC (–3/–1) | ||
| B | Cleaves both sides of target on both strands | BcgI | (10/12) CGANNNNNNTGC (12/10) |
| C | Symmetric or asymmetric target. R and M functions in one polypeptide | GsuI | CTGGAG (16/14) |
| HaeIV | (7/13) GAYNNNNNRTC (14/9) | ||
| BcgI | (10/12) CGANNNNNNTGC (12/10) | ||
| E | Two targets; one cleaved, one an effector | EcoRII | ↓CCWGG |
| NaeI | GCC↓GGC | ||
| F | Two targets, both cleaved coordinately | SfiI | GGCCNNNN↓NGGCC |
| SgrAI | CR↓CCGGYG | ||
| G | Symmetric or asymmetric target. Affected by AdoMet | BsgI | GTGCAG (16/14) |
| Eco57I | CTGAAG (16/14) | ||
| H | Symmetric or asymmetric target. Similar to Type I gene structure | BcgI | (10/12) CGANNNNNNTGC (12/10) |
| AhdI | GACNNN↓NNGTC | ||
| M | Subtype IIP or IIA. Require methylated target | DpnI | Gm6 A↓TC |
| P | Symmetric target and cleavage sites | EcoRI | G↓AATTC |
| PpuMI | RG↓GWCCY | ||
| BslI | CCNNNNN↓NNGG | ||
| S | Asymmetric target and cleavage sites | FokI | GGATG (9/13) |
| MmeI | TCCRAC (20/18) | ||
| T | Symmetric or asymmetric target. R genes are heterodimers | Bpu10I | CCTNAGC (–5/–2)b |
| BslI | CCNNNNN↓NNGG |
aNote that not all subtypes are mutually exclusive. E.g. BslI is of subtype P and T.
bThe abbreviation indicates double strand cleavage as shown below:
5′ C C↓T N A G C
3′ G G A N T↑C G