1. A leucine-rich repeat peptide derived from the Drosophila Toll receptor forms extended filaments with a beta-sheet structure.
- Author
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Gay NJ, Packman LC, Weldon MA, and Barna JC
- Subjects
- Amino Acid Sequence, Animals, Cell Adhesion, Chromatography, High Pressure Liquid, Circular Dichroism, Drosophila genetics, Insect Hormones genetics, Kinetics, Leucine-Rich Repeat Proteins, Membrane Glycoproteins genetics, Models, Molecular, Molecular Sequence Data, Protein Binding, Protein Conformation, Proteins genetics, Receptors, Cell Surface genetics, Solutions, Toll-Like Receptors, Drosophila chemistry, Drosophila Proteins, Insect Hormones chemistry, Leucine chemistry, Membrane Glycoproteins chemistry, Proteins chemistry, Receptors, Cell Surface chemistry
- Abstract
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.
- Published
- 1991
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