Bacterial outer membrane

Not to be confused with Bacterial capsule.
Structure of gram-negative cell envelope
Lipopolysaccharide-assembly, LptC-related
Identifiers
SymbolLptC
PfamPF06835
Pfam clanCL0259
InterProIPR010664
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary
Lipopolysaccharide-assembly
Identifiers
SymbolLptE
PfamPF04390
InterProIPR007485
TCDB1.B.42
OPM superfamily412
OPM protein4q35
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary

The bacterial outer membrane is found in gram-negative bacteria. Gram-negative bacteria form two lipid bilayers in their cell envelopes - an inner membrane (IM) that encapsulates the cytoplasm, and an outer membrane (OM) that encapsulates the periplasm.[1]

The composition of the outer membrane is distinct from that of the inner cytoplasmic cell membrane - among other things, the outer leaflet of the outer membrane of many gram-negative bacteria includes a complex lipopolysaccharide whose lipid portion acts as an endotoxin - and in some bacteria such as E. coli it is linked to the cell's peptidoglycan by Braun's lipoprotein.

Porins can be found in this layer.[2]

  1. ^ Yeow J, Luo M, Chng SS (December 2023). "Molecular mechanism of phospholipid transport at the bacterial outer membrane interface". Nat Commun. 14 (1): 8285. doi:10.1038/s41467-023-44144-8. PMC 10719372. PMID 38092770.
  2. ^ van der Ley P, Heckels JE, Virji M, Hoogerhout P, Poolman JT (September 1991). "Topology of outer membrane porins in pathogenic Neisseria spp". Infection and Immunity. 59 (9): 2963–71. doi:10.1128/IAI.59.9.2963-2971.1991. PMC 258120. PMID 1652557.