Anionic lipid binding to the foreign protein MGS provides a tight coupling between phospholipid synthesis and protein overexpression in Escherichia coli

Biochemistry. 2013 Aug 20;52(33):5533-44. doi: 10.1021/bi400616n. Epub 2013 Aug 5.

Abstract

Certain membrane proteins involved in lipid synthesis can induce formation of new intracellular membranes in Escherichia coli, i.e., intracellular vesicles. Among those, the foreign monotopic glycosyltransferase MGS from Acholeplasma laidlawii triggers such massive lipid synthesis when overexpressed. To examine the mechanism behind the increased lipid synthesis, we investigated the lipid binding properties of MGS in vivo together with the correlation between lipid synthesis and MGS overexpression levels. A good correlation between produced lipid quantities and overexpressed MGS protein was observed when standard LB medium was supplemented with four different lipid precursors that have significant roles in the lipid biosynthesis pathway. Interestingly, this correlation was highest concerning anionic lipid production and at the same time dependent on the selective binding of anionic lipid molecules by MGS. A selective interaction with anionic lipids was also observed in vitro by (31)P NMR binding studies using bicelles prepared with E. coli lipids. The results clearly demonstrate that the discriminative withdrawal of anionic lipids, especially phosphatidylglycerol, from the membrane through MGS binding triggers an in vivo signal for cells to create a "feed-forward" stimulation of lipid synthesis in E. coli. By this mechanism, cells can produce more membrane surface in order to accommodate excessively produced MGS molecules, which results in an interdependent cycle of lipid and MGS protein synthesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetates / metabolism
  • Acholeplasma laidlawii / enzymology*
  • Acholeplasma laidlawii / genetics
  • Anions / chemistry
  • Anions / metabolism
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Binding, Competitive
  • Electrophoresis, Polyacrylamide Gel
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism
  • Glucosyltransferases / chemistry
  • Glucosyltransferases / genetics
  • Glucosyltransferases / metabolism*
  • Lipid Bilayers / chemistry
  • Lipid Bilayers / metabolism
  • Magnetic Resonance Spectroscopy
  • Membrane Lipids / chemistry
  • Membrane Lipids / metabolism*
  • Models, Molecular
  • Multivariate Analysis
  • Mutation
  • Phospholipids / biosynthesis*
  • Phospholipids / chemistry
  • Protein Binding
  • Protein Structure, Tertiary
  • Spectroscopy, Fourier Transform Infrared
  • Transformation, Genetic

Substances

  • Acetates
  • Anions
  • Bacterial Proteins
  • Escherichia coli Proteins
  • Lipid Bilayers
  • Membrane Lipids
  • Phospholipids
  • Glucosyltransferases
  • 1,2-diacylglycerol 3-glucosyltransferase