Table 2. Non-Vir Genes Within Predicted Operons Encoding the Rickettsia T4SS.
| Islet1 | vir 2 | Associated non-Vir genes3 | Distribution4 |
| A | B3 | argB, acetylglutamate kinase | Br, Bo, Fe, Ak, Ri, Rw |
| CHP, 95 aa | Br, Bo, Fe, Ak, Ri | ||
| GTP-binding CHP, 212 aa | Fe, Ak, Ri, Rw | ||
| A | B3-B4a | argB, acetylglutamate kinase | Ma |
| GTP-binding CHP, 213 aa | Ma | ||
| A | B3-B6c | putative ORF (fgenesb), 61 aa | Af |
| argB, acetylglutamate kinase | Co, Si, Af | ||
| GTP-binding CHP, 213 aa | Co, Si, Af | ||
| putative ORF (fgenesb), 56 aa | Co, Si, Af | ||
| A | B6e | vapB, antitoxin of VapB/VapC system | Fe |
| vapC2, COG1487: PIN domain protein | Fe | ||
| C | B8a-B9a | mrpD, Na(+)/H(+) antiporter subunit D | Co, Si, Af |
| mrpC, Na(+)/H(+) antiporter subunit C | Br, Ca, Fe, all SFG genomes | ||
| putative ORF (fgenesb), 49 aa | Fe | ||
| C | B9a | mrpC, Na(+)/H(+) antiporter subunit C | Bo |
| C | D4 | gppA, GTP dp pyrophosphatase | All 13 genomes |
| vapB1, antitoxin of VapB/VapC system | Br, Bo | ||
| vapC1, toxin of VapB/VapC system | Br, Bo | ||
| ndhF, NAD(P)H dehydrogenase 5 | Br | ||
| ptrB, protease 2 | Br, Bo | ||
| D | B1 | COG0536, predicted GTPase | Br |
| putative ORF (fgenesb), 84 aa | Bo | ||
| putative ORF (fgenesb), 72 aa | Bo | ||
| HP, 101 aa | Fe | ||
| CHP, ∼171 aa | All 13 genomes | ||
| HP, ∼130 | Br, Fe | ||
| rickettsial palindromic element | Fe | ||
| E | B4b | HP, 74 aa | Fe |
1
Corresponding to islets A (virB3-virB6e), C (virB9a-virD4), D (virB1), E (virB4b) (See Figure 9 ).
2
According to operon prediction by fgenesb [143].
3
Consensus annotation from PATRIC [80] or fgenesb prediction. HP = hypothetical protein, CHP = conserved hypothetical protein.
4
Taxa included within operon prediction. Underlined taxa depict split ORFs.