Table 2.
Selectively released proteins that exhibit altered abundance in supernatant in response to high salt conditions
| Protein | Description | Fold changea | ||
|---|---|---|---|---|
| 1.0% vs. 0.5% | 1.25% vs. 0.5% | Predicted cleavage siteb | ||
| Downregulated | ||||
| HP0089 | Pfs; Mtn; MqnB | (0.75) | 0.44 | - |
| HP0966 | P-loop NTPase and CrfC domain containing protein | (0.73) | 0.24 | - |
| HP1526 | exodeoxyribonuclease (LexA) | (0.86) | 0.41 | - |
| Upregulated | ||||
| HP0097 | hypothetical protein | 2.05 | 2.55 | 15–16 |
| HP0127 | outer membrane protein (Omp4, HorB) | 5.62 | 19.46 | 20–21 |
| HP0130 | hypothetical protein | (1.92) | 2.35 | 17–18 |
| HP0227 | outer membrane protein (Omp5, HopM) | 21.78 | 23.57 | 18–19 |
| HP0229 | outer membrane protein (Omp6, HopA) | 9.40 | 14.53 | 16–17 |
| HP0252 | outer membrane protein (Omp7, HopF) | 10.24 | 27.37 | 23–24 |
| HP0317 | outer membrane protein (Omp9, HopU) | 3.10 | 6.29 | 20–21 |
| HP0472 | outer membrane protein (Omp11, HorE) | (1.62) | 2.19 | 18–19 |
| HP0671 | outer membrane protein (Omp14, HorF) | 7.93 | 27.37 | 23–24 |
| HP0686 | iron(III) dicitrate transport protein (FecA1) | 12.55 | 27.37 | 17–18 |
| HP0709 | S-adenosylmethionine hydrolase | 3.48 | 3.09 | 21–22 |
| HP0710 | putative outer membrane protein | 6.53 | 16.45 | 16–17 |
| HP0797 | flagellar sheath adhesin (HpaA) | 6.14 | 13.20 | 27–28 |
| HP0863 | lipoprotein, putative; plasminogen-binding protein (PgbB) | 5.62 | 19.46 | 17–18 |
| HP0884 | hypothetical protein | 2.15 | 2.95 | - |
| HP0887 | vacuolating cytotoxin (VacA) | 8.77 | 10.58 | 33–34 |
| HP0896 | outer membrane protein (Omp19, BabB) | (1.25) | 5.52 | 19–20 |
| HP0912 | outer membrane protein (Omp20, HopC, AlpA) | 5.85 | 11.74 | 21–22 |
| HP0913 | outer membrane protein (Omp21, HopB, AlpB) | 2.52 | 6.52 | 41–42 |
| HP1083 | putative outer membrane protein | 4.19 | 7.42 | 26–27 |
| HP1117 | hypothetical secreted protein (HcpX) | (1.43) | 3.17 | 23–24 |
| HP1126 | colicin tolerance-like protein (TolB) | 2.10 | 2.70 | 16–17 |
| HP1177 | outer membrane protein (Omp27, HopQ) | 2.96 | 7.24 | 21–22 |
| HP1243 | outer membrane protein (Omp28, BabA) | 17.16 | 74.74 | 20–21 |
| HP1376 | (3R)-hydroxymyristoyl-(acyl carrier protein) dehydratase (FabZ) | (1.14) | 2.26 | - |
| HP1395 | outer membrane protein (Omp30, HorL) | (1.74) | 4.61 | 21–22 |
| HP1456 | membrane-associated lipoprotein (Lpp20) | 2.16 | 3.63 | 21–22 |
| HP1461 | cytochrome c551 peroxidase | 7.38 | 2.92 | 18–19 |
| HP1469 | outer membrane protein (Omp31, HorJ) | 2.43 | 3.90 | 17–18 |
| HP1501 | outer membrane protein (Omp32, HorK) | 4.19 | 19.13 | - |
| HP1512 | iron-regulated outer membrane protein (FrpB) | 3.51 | 10.25 | 21–22 |
To identify selectively released proteins that differed in proportional abundance in the culture supernatant in response to salt concentration, we analyzed proteomic data for the proteins listed in Suppl. Table S1. The fold change in response to high salt conditions was calculated as a ratio (total spectral counts from 24 h and 36 h time points in 1.0% or 1.25% high salt conditions compared to total spectral counts in the 0.5% condition). The analysis was restricted to proteins with ≥10 total assigned spectral counts in either the 0.5% NaCl condition or high salt conditions. Proteins with fold change values >2 or <2 were considered salt-responsive. The proteins listed met these criteria in at least one of the two high salt conditions. Values in parentheses did not have fold values > 2 for that condition or did not meet the criteria for ≥10 total assigned spectral counts.
Predicted signal sequence cleavage site, based on use of SignalP 5.0 [71]. Numbers represent positions of amino acids at the site of predicted cleavage. Dash (−) indicates that no signal sequence is predicted.