Table 1.
Comparison of general features of iteron plasmid and chromosomal DNA replication initiation.
| Bacterial chromosome | Iteron plasmids | |
|---|---|---|
| Replication initiator | DnaA | Rep, DnaA |
| Binding sites for initiator | Strong and weak DnaA-boxes | DnaA-boxes for DnaA |
| Iterons for Rep | ||
| Weak binding sites ? | ||
| DNA binding domain of initiator | DNA binding domain (DBD) AAA+ domain | Winged Helix domain (WH) |
| Nucleotide binding by initiator | + | Rep protein ? |
| DnaA protein ? | ||
| Oligomer formation by initiator protein | + | Rep oligomers ? |
| Rep-DnaA oligomers ? | ||
| Binding of initiator to dsDNA | + | Rep protein + |
| DnaA protein + (in Pseudomonas spp. DnaA is dispensable) | ||
| Binding of initiator to ssDNA | + | Rep protein + |
| DnaA protein ? | ||
| Assistance of architectural proteins: IHF, HU | More efficient oriC-dependent DNA replication | More efficient plasmid origin-dependent DNA replication |
| HU is required for replication of some plasmids | ||
| Interaction of initiator with helicase DnaB | + | Rep + |
| DnaA + |