TABLE 1.
Overview of penicillin-binding proteins from B. subtilis, E. coli, S. aureus, and S. pneumoniae
| Organism | Class | Gene (reference[s]) | Protein | Function, expressiona (reference[s]) | Localization (method[s])b (reference[s]) |
|---|---|---|---|---|---|
| B. subtilis | A | ponA (154) | PBP1a/b | Cell division-specific TG/TPase (170), veg (154) | Septal (IF, GFP) (141,170, 171) |
| pbpD (157) | PBP4 | Not known, veg (157) | Distributed along membrane with distinct spots at periphery (GFP) (171) | ||
| pbpF (156) | PBP2c | Synthesis of spore PG (116), veg, late stages of spo (156) | Distributed along membrane, redistributed to prespore during sporulation (GFP) (169,171) | ||
| pbpG (143) | PBP2d | Synthesis of spore PG (116), spo (143) | Distributed along membrane (GFP) (171); redistributed to prespore during sporulation (169) | ||
| B | pbpA (125) | PBP2a | Synthesis of lateral wall (202), veg (125) | Evenly distributed along the membrane (GFP) (171) | |
| pbpH (202) | PbpH | Synthesis of lateral wall, veg (202) | Evenly distributed along the membrane (GFP) (171) | ||
| pbpB (215) | PBP2b | Cell division-specific TPase (32), veg, spo (215) | Septal (IF, GFP) (32,171) | ||
| pbpC (126) | PBP3 | Not known, veg, low expression during spo (126) | Distinct foci and bands at cell periphery (GFP) (171) | ||
| spoVD (30) | SpoVD | Synthesis of spore PG, spo (30) | Not known | ||
| pbpI (203) | PBP4b | Not known, spo (203) | Evenly distributed along the membrane (GFP) (171) | ||
| LMW carboxypeptidase | dacA (185) | PBP5 | Major dd-carboxypeptidase (104) | Distributed along membrane with distinct spots at periphery (GFP) (171) | |
| dacB (21) | PBP5* | Control of peptide cross-linking in spore PG (153), spo (21) | Not known | ||
| dacC (142) | PBP4a | Not known, late stationary phase (142) | Distinct foci and bands at cell periphery (GFP) (171) | ||
| dacF (211) | DacF | Control of peptide cross-linking in spore PG (153), spo (211) | Not known | ||
| LMW endopeptidase | pbpE (155) | PBP4* | Not known, spo (155) | Distinct foci and bands at cell periphery (GFP) (169) | |
| pbpX | PbpX | Not known, veg (169) | Septal, spiral outgrowth to both asymmetric septa during sporulation (169,171) | ||
| E. coli | A | ponA (19) | PBP1a | General PG synthesis | |
| ponB (19) | PBP1b (α, β, γ) | General PG synthesis | |||
| pbpC (172) | PBP1c | Functions as a TGase only; binds to PBPs1B, −2, and −3 and MltA (172) | |||
| B | pbpA (4) | PBP2 | Elongation-specific TPase (183) | Spot-like pattern along lateral membrane, division site (GFP) (36) | |
| pbpB or ftsI (127) | PBP3 | Cell division-specific TPase (183) | Division septum (IF, GFP) (200, 205) | ||
| LMW carboxypeptidase | dacA (20) | PBP5 | Control of cell shape (117, 129,130) | ||
| dacC (20) | PBP6 | ||||
| dacD (7) | PBP6b | ||||
| LMW endopeptidase | dacB (97) | PBP4 | Control of cell shape in concert with PBP5 (117) | ||
| pbpG (75) | PBP7 | Control of cell shape in concert-with PBP5 (117) | |||
| mepA (92) | MepA | Penicillin-insensitive endopeptidase | |||
| β-Lactamase | ampC (76) | AmpC | Affects cell shape (76) | ||
| ampH (76) | AmpH | Affects cell shape (76) | |||
| S. aureus | A | pbp2 or pbpB (69,124) | PBP2 | Cell division (147) | Division septum (IF, GFP) (146, 147) |
| B | pbpA (160) | PBP1 | Unknown | Not known | |
| pbpC (145) | PBP3 | Unknown | Not known | ||
| mecA (181) | PBP2A or PBP2′ | Protein from extraspecies origin that confers beta-lactam resistance (71, 161) | Not known | ||
| LMW transpeptidase | pbpD or pbp4 (49) | PBP4 | Secondary cross-linking of PG (212) | Not known | |
| S. pneumoniae | A | pbp1a | PBP1a | Cell division (122) | Septal (122) |
| PBP1b | Unknown | Septal or equatorial (122) | |||
| pbp2a | PBP2a | Peripheral cell wall synthesis (122) | Equatorial (122) | ||
| B | pbp2x or pbpX (101) | PBP2x | Cell division (122) | Septal (122) | |
| pbp2b | PBP2b | Peripheral cell wall synthesis (122) | Equatorial (122) | ||
| LMW dd-carboxypeptidase | dacA (176) | PBP3 | Regulates cross-linking degree; coordination of the division process (120) | Evenly distributed in both hemispheres and absent from the future division site (120) |
a
For B. subtilis the expression or transcription factor dependency of most pbp genes has been determined and is indicated. veg, expression during vegetative growth; spo, expression during sporulation; TGase, transglycosylase; TPase, transpeptidase.
b
I, immunofluorescence; GFP, fluorescence of a GFP fusion.