pISSN 1225-7117
eISSN 2288-8268
Key features of widely used CRISPR-Cas systems in pathogen detection methods
| Class II | Type II | Type V | Type VI | |||
|---|---|---|---|---|---|---|
| Cas | Cas9 | dCas9 | Cas12a | Cas12b | Cas14 | Cas13a |
| Length (a.a.) | 1000-1700 | 1200-1300 | ~1300 | 400-700 | ~1160 | |
| Nuclease domain | HNH, RuvC | Deactivated HNH and RuvC | RuvC | RuvC | RuvC | 2xHEPN |
| Target type (cleavage type) | dsDNA (Blunt end) | N/A | dsDNA(Staggered) or ssDNA(single cut) | ssDNA(single cut) | ssRNA(Degraded) | |
| Collateral cleavage | N/A | N/A | ssDNA | ssDNA | ssDNA | ssRNA |
| PAM/PFS1 Sequence | PAM5’-NGG-3’ | PAM5’-TTTN-3’ | PAM5’-TTN-3’ | Not required | PFS5’-ATC-3’ | |
| TracrRNA requirement | Yes | No | Yes | Yes for Cas14a, no for Cas14b | No | |
1PAM, protospacer adjacent motif; PFS, protospacer flanking sequence