Table 2. Properties of CRISPR–Cas and CRISPR–Cmr systems of representative Sulfolobales members.
Numbers of chromosomal CRISPR loci and the total number of spacers are given for each organism together with the PAMs exhibited by their corresponding protospacers. An asterisk (*) indicates that the PAM sequence is based on comparison of only two sequences [21]. The total number of spacer-acquisition modules, cas6 genes and interference modules are given and additional partial and potentially defective modules are enclosed by parentheses. Acquisition and interference modules are assigned to Type I or Type III CRISPR systems. Spacer-acquisition modules associated specifically with Type III interference modules are rare in archaea. A minus (−) indicates none present.
| Acquisition modules | Interference modules | |||||||
|---|---|---|---|---|---|---|---|---|
| Organism | CRISPR loci | Spacers | PAM | I | III | cas6 gene | I | III |
| S. solfataricus P2 | 6 | 415 | CCN TCN | 2 | − | 3 | 3 | 2 (2) |
| S. islandicus REY15A | 2 | 206 | CCN | 1 | − | 1 | 1 | 2 |
| S. acidocaldarius DSM639 | 5 | 223 | GTN TCN | 1 (1) | − | 3 | 1 | 2 |
| S. tokodaii 7 | 5 | 461 | CCN TCN | 2 | − | 3 | 2 | 3 |
| Acidianus hospitalis W1 | 5 | 123 | TCN CCN | (1) | 1 | 2 | 1 | 1 |
| Metallosphaera sedula | 5 | 386 | CCN ATTAN* | 1 (1) | − | 2 | 1 | 1 |