A leucine-rich repeat peptide derived from the Drosophila Toll receptor forms extended filaments with a beta-sheet structure

FEBS Lett. 1991 Oct 7;291(1):87-91. doi: 10.1016/0014-5793(91)81110-t.


Leucine-rich repeats (LRRs) are 22-28 amino acid-long sequence motifs found in a family of cytoplasmic, membrane and extracellular proteins. There is evidence that LRRs function in signal transduction, cellular adhesion and protein-protein interactions. Here we report unusual properties of a synthetic LRR peptide derived from the sequence of the Drosophila membrane receptor Toll. In neutral solution the peptide forms a gel revealed by electron microscopy to consist of extended filaments approximately 8 nm in thickness. As the gel forms, the circular dichroism spectrum of the peptide solution changes from one characteristic of random coil to one associated with beta-sheet structures. Molecular modelling suggests that the peptide form an amphipathic structure with a predominantly apolar and charged surface. Based on these results, models for the gross structure of the peptides filaments and a possible molecular mechanism for cellular adhesion are proposed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Adhesion
  • Chromatography, High Pressure Liquid
  • Circular Dichroism
  • Drosophila / chemistry*
  • Drosophila / genetics
  • Drosophila Proteins*
  • Insect Hormones / chemistry*
  • Insect Hormones / genetics
  • Kinetics
  • Leucine / chemistry*
  • Leucine-Rich Repeat Proteins
  • Membrane Glycoproteins / chemistry*
  • Membrane Glycoproteins / genetics
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Binding
  • Protein Conformation
  • Proteins / chemistry*
  • Proteins / genetics
  • Receptors, Cell Surface / chemistry*
  • Receptors, Cell Surface / genetics
  • Solutions
  • Toll-Like Receptors


  • Drosophila Proteins
  • Insect Hormones
  • Leucine-Rich Repeat Proteins
  • Membrane Glycoproteins
  • Proteins
  • Receptors, Cell Surface
  • Solutions
  • Tl protein, Drosophila
  • Toll-Like Receptors
  • Leucine