TY - JOUR
T1 - Localization of the terminal steps of O-antigen synthesis in Salmonella typhimurium
AU - McGrath, B. C.
AU - Osborn, M. J.
PY - 1991
Y1 - 1991
N2 - Previous immunoelectron microscopic studies have shown that both the final intermediate in O-antigen synthesis, undecaprenol-linked O polymer, and newly synthesized O-antigenic lipopolysaccharide are localized to the periplasmic face of the inner membrane (C. A. Mulford and M. J. Osborn, Proc. Natl. Acad. Sci. USA 80: 1159-1163, 1983). In vivo pulse-chase experiments now provide further evidence that attachment of O antigen to core lipopolysaccharide, as well as polymerization of O-specific polysaccharide chains, takes place at the periplasmic face of the membrane. Mutants doubly conditional in lipopolysaccharide synthesis [kdsA(Ts) pmi] were constructed in which synthesis of core lipopolysaccharide and O antigen are temperature sensitive and mannose dependent, respectively. Periplasmic orientation of O antigen:core lipopolysaccharide ligase was established by experiments showing rapid chase of undecaprenol-linked D polymer, previously accumulated at 42°C in the absence of core synthesis, into lipopolysaccharide following resumption of core formation at 30°C. In addition, chase of the monomeric G-specific tetrasaccharide unit into lipopolysaccharide was found in similar experiments in an O-polymerase-negative [rfc kdsA(Ts) pmi) mutant, suggesting that polymerization of O chains also occurs at the external face of the inner membrane.
AB - Previous immunoelectron microscopic studies have shown that both the final intermediate in O-antigen synthesis, undecaprenol-linked O polymer, and newly synthesized O-antigenic lipopolysaccharide are localized to the periplasmic face of the inner membrane (C. A. Mulford and M. J. Osborn, Proc. Natl. Acad. Sci. USA 80: 1159-1163, 1983). In vivo pulse-chase experiments now provide further evidence that attachment of O antigen to core lipopolysaccharide, as well as polymerization of O-specific polysaccharide chains, takes place at the periplasmic face of the membrane. Mutants doubly conditional in lipopolysaccharide synthesis [kdsA(Ts) pmi] were constructed in which synthesis of core lipopolysaccharide and O antigen are temperature sensitive and mannose dependent, respectively. Periplasmic orientation of O antigen:core lipopolysaccharide ligase was established by experiments showing rapid chase of undecaprenol-linked D polymer, previously accumulated at 42°C in the absence of core synthesis, into lipopolysaccharide following resumption of core formation at 30°C. In addition, chase of the monomeric G-specific tetrasaccharide unit into lipopolysaccharide was found in similar experiments in an O-polymerase-negative [rfc kdsA(Ts) pmi) mutant, suggesting that polymerization of O chains also occurs at the external face of the inner membrane.
UR - http://www.scopus.com/inward/record.url?scp=0026025516&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026025516&partnerID=8YFLogxK
U2 - 10.1128/jb.173.2.649-654.1991
DO - 10.1128/jb.173.2.649-654.1991
M3 - Article
C2 - 1987157
AN - SCOPUS:0026025516
VL - 173
SP - 649
EP - 654
JO - Journal of Bacteriology
JF - Journal of Bacteriology
SN - 0021-9193
IS - 2
ER -