title: Biosynthesis and assembly of capsular polysaccharides in Escherichia coli.
abstract: Capsules are protective structures on the surfaces of many bacteria. The remarkable structural diversity in capsular polysaccharides is illustrated by almost 80 capsular serotypes in Escherichia coli. Despite this variation, the range of strategies used for capsule biosynthesis and assembly is limited, and E. coli isolates provide critical prototypes for other bacterial species. Related pathways are also used for synthesis and export of other bacterial glycoconjugates and some enzymes/processes have counterparts in eukaryotes. In gram-negative bacteria, it is proposed that biosynthesis and translocation of capsular polysaccharides to the cell surface are temporally and spatially coupled by multiprotein complexes that span the cell envelope. These systems have an impact on both a general understanding of membrane trafficking in bacteria and on bacterial pathogenesis.
authors.affiliation: Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada. cwhitfie@uoguelph.ca
authors.forename: Chris
authors.initials: C
authors.lastname: Whitfield
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D016667:Bacterial Capsules / Q000145:classification / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D015394:Molecular Structure; D019081:O Antigens / Q000737:chemistry; D033903:Periplasmic Proteins / Q000235:genetics / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis* / Q000737:chemistry; D011487:Protein Conformation; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D018528:ATP-Binding Cassette Transporters; D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; C088016:KpsD protein, E coli; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D019081:O Antigens; D033903:Periplasmic Proteins; D011134:Polysaccharides; D011135:Polysaccharides, Bacterial; C404158:Wza protein, E coli; C084729:kpsE protein, E coli; C489586:wzzB protein, E coli; C004275:colanic acid; D011505:Protein-Tyrosine Kinases; C499615:wzc protein, E coli; D010749:Phosphoprotein Phosphatases; C428435:Wzb protein, E coli