An induced folding process characterizes the partial-loss of function mutant LptAI36D in its interactions with ligands

Biochim Biophys Acta. 2015 Oct;1854(10 Pt A):1451-7. doi: 10.1016/j.bbapap.2015.06.013. Epub 2015 Jun 27.

Abstract

Lipopolysaccharide (LPS) is an essential glycolipid of the outer membrane (OM) of Gram-negative bacteria with a tripartite structure: lipid A, oligosaccharide core and O antigen. Seven essential LPS-transport proteins (LptABCDEFG) move LPS to the cell surface. Lpt proteins are linked by structural homology, featuring a β-jellyroll domain that mediates protein-protein interactions and LPS binding. Analysis of LptA-LPS interaction by fluorescence spectroscopy is used here to evaluate the contribution of each LPS moiety in protein-ligand interactions, comparing the wild-type (wt) protein to the I36D mutant. In addition to a crucial role of lipid A, an unexpected contribution emerges for the core region in recognition and binding of Lpt proteins.

Keywords: 1-Anilino-8-naphthalene sulfonate; Binding site; Circular dichroism; Escherichia coli; Fluorescence spectroscopy; Lipopolysaccharide transport.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Substitution
  • Anilino Naphthalenesulfonates
  • Aspartic Acid / chemistry
  • Aspartic Acid / metabolism
  • Biological Transport
  • Carbohydrate Sequence
  • Carrier Proteins / chemistry*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Escherichia coli K12 / chemistry
  • Escherichia coli K12 / genetics
  • Escherichia coli K12 / metabolism*
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism
  • Gene Expression
  • Isoleucine / chemistry
  • Isoleucine / metabolism
  • Ligands
  • Lipopolysaccharides / chemistry*
  • Lipopolysaccharides / metabolism
  • Molecular Sequence Data
  • Mutation*
  • Protein Binding
  • Protein Folding
  • Recombinant Fusion Proteins / chemistry*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Spectrometry, Fluorescence

Substances

  • Anilino Naphthalenesulfonates
  • Carrier Proteins
  • Escherichia coli Proteins
  • Ligands
  • Lipopolysaccharides
  • LptA protein, E coli
  • Recombinant Fusion Proteins
  • Isoleucine
  • Aspartic Acid
  • 1-anilino-8-naphthalenesulfonate