Table 2.
Biochemical characterization of PriA, SubHisA2 and SubTrpF homologs.
| Enzymes | In vivo activity | In vitro activity * | ||||||
|---|---|---|---|---|---|---|---|---|
| ProFAR isomerase (HisA) | PRA isomerase (TrpF) | |||||||
| HisA | TrpF |
KM
(µM) |
kcat
(s−1) |
kcat/KM
(s−1µM−1) |
KM
(µM) |
kcat
(s−1) |
kcat/KM
(s−1µM−1) |
|
| PriA_Org3_B. longum | + | + | 2.7 ± 0.5 | 0.4 ± 0.1 | 0.1 | 6.1 ± 0.1 | 2.1 ± 0.5 | 0.3 |
| PriA_Org1_B. gallicum | + | + | 1.7 ± 0.3 | 0.3 ± 0.1 | 0.2 | 40 ± 9 | 3.5 ± 0.1 | 0.09 |
| PriA_Org6_B. adolescentis | + | + | 17 ± 4.3 | 2.3 ± 0.01 | 0.1 | 21 ± 5 | 0.9 ± 0.2 | 0.04 |
| PriA_Org15_A. urogenitalis | + | + | 4.0 ± 0.9 | 0.2 ± 0.03 | 0.04 | 23 ± 6.5 | 0.5 ± 0.05 | 0.02 |
| PriA_Org22_A. sp. oral taxon 171 | + | + | 3 ± 0.3 | 0.3 ± 0.09 | 0.1 | 8 ± 2 | 0.4 ± 0.1 | 0.04 |
| PriA_Org21_A. oris MG-1 | + | + | 10 ± 2 | 0.2 ± 0.09 | 0.02 | 30 ± 7 | 0.3 ± 0.03 | 0.01 |
| SubHisA2_Org34_A. vaccimaxillae | + | + | ||||||
| SubHisA2_Org36_A. cardiffensis | + | + | 56 ± 17 | 0.14 ± 0.05 | 0.002 | n.d. | n.d. | n.d. |
| SubTrpF_Org10_A. sp. oral taxon 848 | − | + | n.d. | n.d. | n.d. | n.d. | n.d. | 0.0001 |
| SubTrpF_Org13_A. graevenitzii | − | + | ||||||
| SubTrpF_Org39_A. sp. oral taxon 180 | − | + | ||||||
| SubTrpF_Org41_A. odontolyticus | − | + | n.d. | n.d. | n.d. | 8.5 ± 0.9 | 0.15 ± 0.06 | 0.02 |
* Each data point comes from at least three independent determinations using freshly purified enzyme. n.d., activity not detected, even using active-site saturation conditions. Empty entries reflect our inability to properly express and/or solubilize these proteins. The detection limits for the PRA and ProFAR isomerase assay used in the present study are 0.0001 μM−1s−1 and 0.001 μM−1s−1, respectively (Noda-García et al., 2013; Verduzco-Castro et al., 2016; Noda-García et al., 2010).