title: Outer-membrane permeability of bacteria.
abstract: Gram-negative bacteria evolved to survive under the conditions in which a number of hazardous compounds are abundant. The outer membrane which protects the cell interior acts as a barrier against such hazardous agents, yet the cells must incorporate the chemicals that are essential for the cellular activity. The devices that Gram-negative bacteria developed to incorporate such essence are the transmembrane pores. These pores could be subdivided into three categories: (1) pore made of porins has a weak solute selectivity; (2) pore made of lamB protein and tsx proteins hold intermediate solute specificity. and (3) pores for the diffusion of vitamin B12 and ferric ion-chelator complexes have a tight solute specificity. Porins are identified from a number of Gram-negatives and from the outer membrane of mitochondria of various sources. Studies on the diffusion properties of these outer-membrane proteins provided essential information to understand membrane transports.
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000032:analysis / Q000378:metabolism / Q000648:ultrastructure; D002463:Cell Membrane Permeability; D002736:Chloroplasts / Q000378:metabolism / Q000648:ultrastructure; D004755:Enterobacteriaceae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D005290:Ferric Compounds / Q000378:metabolism; D005786:Gene Expression Regulation; D005798:Genes, Bacterial; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D050356:Lipid Metabolism; D008070:Lipopolysaccharides / Q000032:analysis; D008928:Mitochondria / Q000032:analysis / Q000378:metabolism; D009154:Mutation; D010710:Phosphates / Q000378:metabolism; D010743:Phospholipids / Q000032:analysis; D018272:Porins; D011550:Pseudomonas aeruginosa / Q000378:metabolism / Q000648:ultrastructure; D011991:Receptors, Virus / Q000378:metabolism; D013696:Temperature; D014805:Vitamin B 12 / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D005290:Ferric Compounds; D008070:Lipopolysaccharides; D010710:Phosphates; D010743:Phospholipids; D018272:Porins; D011991:Receptors, Virus; C016532:maltoporins; C021076:protein K; D014805:Vitamin B 12