Download MendeleyHigh-Resolution Structure of a Self-Assembly-Competent Form of a Hydrophobic Peptide Captured in a Soluble β-Sheet Scaffold.
Makabe, K., Biancalana, M., Yan, S., Tereshko, V., Gawlak, G., Miller-Auer, H., Meredith, S.C., Koide, S.(2008) J Mol Biol 378: 459-467
- PubMed: 18367205
- DOI: https://doi.org/10.1016/j.jmb.2008.02.051
- Primary Citation of Related Structures:
2I5V - PubMed Abstract:
beta-Rich self-assembly is a major structural class of polypeptides, but still little is known about its atomic structures and biophysical properties. Major impediments for structural and biophysical studies of peptide self-assemblies include their insolubility and heterogeneous composition. We have developed a model system, termed peptide self-assembly mimic (PSAM), based on the single-layer beta-sheet of Borrelia outer surface protein A. PSAM allows for the capture of a defined number of self-assembly-like peptide repeats within a water-soluble protein, making structural and energetic studies possible. In this work, we extend our PSAM approach to a highly hydrophobic peptide sequence. We show that a penta-Ile peptide (Ile(5)), which is insoluble and forms beta-rich self-assemblies in aqueous solution, can be captured within the PSAM scaffold in a form capable of self-assembly. The 1.1-A crystal structure revealed that the Ile(5) stretch forms a highly regular beta-strand within this flat beta-sheet. Self-assembly models built with multiple copies of the crystal structure of the Ile(5) peptide segment showed no steric conflict, indicating that this conformation represents an assembly-competent form. The PSAM retained high conformational stability, suggesting that the flat beta-strand of the Ile(5) stretch primed for self-assembly is a low-energy conformation of the Ile(5) stretch and rationalizing its high propensity for self-assembly. The ability of the PSAM to "solubilize" an otherwise insoluble peptide stretch suggests the potential of the PSAM approach to the characterization of self-assembling peptides.
Organizational Affiliation:
Department of Biochemistry and Molecular Biology, The University of Chicago, 929 E. 57th Street, Chicago, IL 60637, USA.
