Protein complexes of the Escherichia coli cell envelope

• Protein complexes are an intrinsic aspect of life in the membrane. Knowing which proteins are assembled in these complexes is therefore essential to understanding protein function(s). Unfortunately, recent high throughput protein interaction studies have failed to deliver any significant information on proteins embedded in the membrane, and many membrane protein complexes remain ill defined. In this study, we have optimized the blue native-PAGE technique for the study of membrane protein complexes in the inner and outer membranes of Escherichia coli. In combination with second dimension SDS-PAGE and mass spectrometry, we have been able to identify 43 distinct protein complexes. In addition to a number of well characterized complexes, we have identified known and orphan proteins in novel oligomeric states. For two orphan proteins, YhcB and YjdB, our findings enable a tentative functional assignment. We propose that YhcB is a hitherto unidentified additional subunit of the cytochrome bd oxidase and that YjdB, which co-localizes with the ZipA protein, is involved in cell division. Our reference two-dimensional blue native-SDS-polyacrylamide gels will facilitate future studies of the assembly and composition of E. coli membrane protein complexes during different growth conditions and in different mutant backgrounds.

Ämnesord

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

Nyckelord

Blotting; Western

Cell Cycle Proteins/chemistry/*pharmacology

Cell Division

Cell Membrane/*metabolism

Cytochromes/metabolism

Dimerization

Electron Transport Chain Complex Proteins/metabolism

Electrophoresis; Gel; Two-Dimensional

Electrophoresis; Polyacrylamide Gel

Escherichia coli/metabolism/*physiology

Escherichia coli Proteins/chemistry/metabolism/pharmacology/*physiology

Ions/chemistry

Macromolecular Substances/chemistry

Mass Spectrometry

Membrane Proteins/chemistry

Mutation

Oxidoreductases/chemistry/metabolism/*pharmacology

Protein Binding

Spectrometry; Mass; Matrix-Assisted Laser Desorption-Ionization

Biochemistry

Biokemi

Biogeochemistry

biogeokemi

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)