Table 4 Functional diversity of the experimentally characterized biosensing effectors of class 2 CRISPR–Cas systems
From: Programmable Biosensors Based on RNA-Guided CRISPR/Cas Endonuclease
CRISPR/Cas type | Size (aa) | Nuclease domain | PAM (5′) | Stable binding specificity/bp | Substrate preference | Substrate | Cleavage pattern | Reference |
|---|---|---|---|---|---|---|---|---|
Cas9 | ~ 1300 | RuvC, HNH | NGG | 9 | / | dsDNA | Blunt ends | [65] |
Cas12a(Cpf1) | ~ 1300 | RuvC, Nuc | TTTN | 17 | / | dsDNA | Staggered ends | [77] |
Cas12b(C2c1) | ~ 1100 | RuvC, Nuc | TTN | 17 | / | dsDNA | Staggered ends | [78] |
Cas13a(C2c2) | ~ 1300 | 2 HEPN domains | Non-G, PFS | 20 | di-AC, di-AU | ssRNA | / | [79] |
Cas13b | ~ 1200 | 2 HEPN domains | 5-A, U, G, and 3′-NAN, NNA | 14 | di-UC, di-GA | ssRNA | / | |
Cas13d | ~ 900 | 2 HEPN domains | No PFS preference | 18 | / | ssRNA | / | |
Cas14a1 | ~ 400 | RuvC, Nuc | No PFS preference | / | / | ssDNA | / | [26] |