TABLE 1.
Proteins tested as potential biomarkers in this study
| Locus taga | Protein type | Protein name | Distinctive domain(s)b | Putative function | Immunogenicitye |
|---|---|---|---|---|---|
| BA0345 | Alkylhydroxyperoxide reductase | AhpC | Oxidative stress response | ++ | |
| BA0796 | Hypothetical | S, SH3 (two), 3D | Unknown | ++ | |
| BA0799c | Hypothetical | S, HlyD | Unknown | ++ | |
| BA0898 | Alanine amidase | CwlB | S, SLH | Cell wall hydrolysis | ++ |
| BA1295 | Immune inhibitor | InhA1 | S | Zn protease | +/− |
| BA1952 | NlpC/P60 family endopeptidase | S, SH3 (two), NlpC/P60 | Cell wall hydrolysis | ++ | |
| BA3367 | γ Phage receptor | GamR | S, LPXTG | Unknown | ++ |
| BA3660 | Serine protease | HtrA | S | Chaperone, secretion, stress response | ++ |
| BA4787 | Iron-regulated determinant | IsdK | S, NEAT | Hemoglobin uptake, iron consumption | ++ |
| BA5427d | Endopeptidase | LytE | S, NlpC/P60 | Cell wall hydrolysis | +/− |
Proteins are arranged in ascending order according to genomic locus tag number (www.ncbi.nlm.nih.gov).
Domains which are inherently related to the functional annotation of the proteins are not indicated. S, export signal peptide; SH3, Src homology domain; HlyD, homology domain in some proteins involved in toxin secretion in gram-negative bacteria; 3D, cation binding domain involved in protein-protein interactions; SLH, S-layer homology domain; NEAT, “near transporter” repeat domain present in ORFs adjacent to iron transporters in gram-positive bacteria; NlpC/P60, cell wall peptidase family domain; LPXTG, gram-positive sortase domain.
The product of the BA0799 gene is annotated as a hypothetical protein of unknown function in the genomic database, yet we noted that it may represent a component of an ABC transporter, based on its genomic location and sequence homology (22).
The product of the BA5427 locus is functionally annotated in the database as the B. anthracis homologue of the known LytE Bacillus cell wall hydrolase, as indicated in the table. We note that the protein indeed exhibits an LytE-like NlpC/P60 protease domain, yet it lacks the characteristic LysM domains (necessary for peptidoglycan targeting).