Examination of AsmA and its effect on the assembly of Escherichia coli outer membrane proteins

Ming Deng, Rajeev Misra

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

asmA mutations were isolated as extragenic suppressors of an OmpF assembly mutant, OmpF315. This suppressor locus produced a protein that was present in extremely low levels and could only be visualized by Western blotting in cells where AsmA expression was induced from a plasmid. Detailed fractionation analyses showed that AsmA localized with the inner membrane. Curiously, however, the mutant OmpF assembly step influenced by AsmA occurred in the outer membrane, perhaps indicating an indirect involvement of AsmA in the assembly of outer membrane proteins. Biochemical examination of the outer membrane showed that asmA null mutations reduce lipopolysaccharide (LPS) levels, thereby lowering the ratios of glycerolphospholipids to LPS and envelope proteins to LPS in the outer membrane. Despite these quantitative alterations, no apparent structural changes in LPS or major phospholipids were noted. Reduced LPS levels in asmA mutants indicate a possible role of AsmA in LPS biogenesis. Data presented in this study suggest that asmA-mediated OmpF assembly suppression may have been achieved by altering the outer membrane fluidity, thus making it more amenable for the assembly of mutant proteins.

Original languageEnglish (US)
Pages (from-to)605-612
Number of pages8
JournalMolecular Microbiology
Volume21
Issue number3
StatePublished - 1996

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Lipopolysaccharides
Membrane Proteins
Escherichia coli
Membranes
Mutation
Membrane Fluidity
Mutant Proteins
Phospholipids
Proteins
Plasmids
Western Blotting

ASJC Scopus subject areas

  • Molecular Biology
  • Microbiology

Cite this

Examination of AsmA and its effect on the assembly of Escherichia coli outer membrane proteins. / Deng, Ming; Misra, Rajeev.

In: Molecular Microbiology, Vol. 21, No. 3, 1996, p. 605-612.

Research output: Contribution to journalArticle

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