Table 1.
Substrate specificity of orthologous aaPGS enzymes, cellular aaPG content, and acidic induction
| Strain | Enzyme/ORF | Method(s) for specificity determination (reference)a | Specificity (reference) | % aaPG of overall lipid content (reference)b | Acidic inductionc |
|---|---|---|---|---|---|
| Bacillus anthracis strain Sterne | BAS1375 | ACTD, E (77) | L-PG (77) | 10 (77) | ND |
| Bacillus licheniformis ATCC 14580 | YfiX | ACTD, C, D, E | L-PG | 3 | – |
| Bacillus thuringiensis ATCC 10792 | Bthur0008_13400 | AFL, BFL, C, D | L-PG | 10 | – |
| Streptococcus thermophilus ATCC 19258 | stu1256 | ACTD, C, E | L-PG | 10 | ND |
| Pseudomonas aeruginosa UCBPP-PA14 | PA14_52350 | C | A-PG | 0.5/4 | + |
| Pseudomonas putida KT2440 | PP_1202 | C | A-PG | 0.5/5 | + |
| Burkholderia phymatum STM 815 | Bphy_4019 | AFL, BFL, D | A-PG | 0.5 | – |
| Kineococcus radiotolerans SRS 30216 | Krad_4555 | AFL, BFL, D | A-PG | 0.5 | – |
| Paenibacillus polymyxa ATCC 842 | A-PGS | AFL, BFL, C, D | A-PG | 4 | – |
| Methanosarcina barkeri ATCC 29787 | Mbar_A2435 | BFL | A-PG | ND | ND |
Methods for specificity determination using either recombinant full-length protein (FL) or C-terminal domain (CTD): A, lipid analysis by molybdatophosphoric acid staining of E. coli cells producing the recombinant protein; B, in vitro assay using 14C-amino acids. Specificity determination using native strains: C, lipid analysis by molybdatophosphoric acid staining; D, lipid analysis by ninhydrin staining; E, mass spectrometry of respective lipid spot.
Cellular aaPG amounts have been determined from two-dimensional TLC analyses. Values are related to the overall lipid content. The potential induction of aaPG synthesis under acidic growth conditions was analyzed as described in Materials and Methods, and values for neutral conditions (pH 7.3)/acidic conditions (pH 5.3) are indicated. ND, not determined.
ND, not determined; −, no increase of cellular aaPG concentrations; +, significantly elevated cellular aaPG concentrations under acidic growth conditions (see Fig. S2 and S3 in the supplemental material).