TABLE 1.

Overview of penicillin-binding proteins from B. subtilis, E. coli, S. aureus, and S. pneumoniae

OrganismClassGene (reference[s])ProteinFunction, expressiona (reference[s])Localization (method[s])b (reference[s])
B. subtilisAponA (154)PBP1a/bCell division-specific TG/TPase (170), veg (154)Septal (IF, GFP) (141,170, 171)
pbpD (157)PBP4Not known, veg (157)Distributed along membrane with distinct spots at periphery (GFP) (171)
pbpF (156)PBP2cSynthesis of spore PG (116), veg, late stages of spo (156)Distributed along membrane, redistributed to prespore during sporulation (GFP) (169,171)
pbpG (143)PBP2dSynthesis of spore PG (116), spo (143)Distributed along membrane (GFP) (171); redistributed to prespore during sporulation (169)
BpbpA (125)PBP2aSynthesis of lateral wall (202), veg (125)Evenly distributed along the membrane (GFP) (171)
pbpH (202)PbpHSynthesis of lateral wall, veg (202)Evenly distributed along the membrane (GFP) (171)
pbpB (215)PBP2bCell division-specific TPase (32), veg, spo (215)Septal (IF, GFP) (32,171)
pbpC (126)PBP3Not known, veg, low expression during spo (126)Distinct foci and bands at cell periphery (GFP) (171)
spoVD (30)SpoVDSynthesis of spore PG, spo (30)Not known
pbpI (203)PBP4bNot known, spo (203)Evenly distributed along the membrane (GFP) (171)
LMW carboxypeptidasedacA (185)PBP5Major 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)PBP4aNot known, late stationary phase (142)Distinct foci and bands at cell periphery (GFP) (171)
dacF (211)DacFControl of peptide cross-linking in spore PG (153), spo (211)Not known
LMW endopeptidasepbpE (155)PBP4*Not known, spo (155)Distinct foci and bands at cell periphery (GFP) (169)
pbpXPbpXNot known, veg (169)Septal, spiral outgrowth to both asymmetric septa during sporulation (169,171)
E. coliAponA (19)PBP1aGeneral PG synthesis
ponB (19)PBP1b (α, β,γ )General PG synthesis
pbpC (172)PBP1cFunctions as a TGase only; binds to PBPs1B, −2, and −3 and MltA (172)
BpbpA (4)PBP2Elongation-specific TPase (183)Spot-like pattern along lateral membrane, division site (GFP) (36)
pbpB or ftsI (127)PBP3Cell division-specific TPase (183)Division septum (IF, GFP) (200, 205)
LMW carboxypeptidasedacA (20)PBP5Control of cell shape (117, 129,130)
dacC (20)PBP6
dacD (7)PBP6b
LMW endopeptidasedacB (97)PBP4Control of cell shape in concert with PBP5 (117)
pbpG (75)PBP7Control of cell shape in concert-with PBP5 (117)
mepA (92)MepAPenicillin-insensitive endopeptidase
β-LactamaseampC (76)AmpCAffects cell shape (76)
ampH (76)AmpHAffects cell shape (76)
S. aureusApbp2 or pbpB (69,124)PBP2Cell division (147)Division septum (IF, GFP) (146, 147)
BpbpA (160)PBP1UnknownNot known
pbpC (145)PBP3UnknownNot known
mecA (181)PBP2A or PBP2′Protein from extraspecies origin that confers beta-lactam resistance (71, 161)Not known
LMW transpeptidasepbpD or pbp4 (49)PBP4Secondary cross-linking of PG (212)Not known
S. pneumoniaeApbp1aPBP1aCell division (122)Septal (122)
PBP1bUnknownSeptal or equatorial (122)
pbp2aPBP2aPeripheral cell wall synthesis (122)Equatorial (122)
Bpbp2x or pbpX (101)PBP2xCell division (122)Septal (122)
pbp2bPBP2bPeripheral cell wall synthesis (122)Equatorial (122)
LMW dd-carboxypeptidasedacA (176)PBP3Regulates 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.