Download MendeleyAromatic cluster mutations produce focal modulations of beta-sheet structure.
Biancalana, M., Makabe, K., Yan, S., Koide, S.(2015) Protein Sci 24: 841-849
- PubMed: 25645104 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.1002/pro.2657
- Primary Citation Related Structures:
2OY5, 2PI3, 3AUM - PubMed Abstract:
Site-directed mutagenesis is a powerful tool for altering the structure and function of proteins in a focused manner. Here, we examined how a model β-sheet protein could be tuned by mutation of numerous surface-exposed residues to aromatic amino acids. We designed these aromatic side chain "clusters" at highly solvent-exposed positions in the flat, single-layer β-sheet of Borrelia outer surface protein A (OspA). This unusual β-sheet scaffold allows us to interrogate the effects of these mutations in the context of well-defined structure but in the absence of the strong scaffolding effects of globular protein architecture. We anticipated that the introduction of a cluster of aromatic amino acid residues on the β-sheet surface would result in large conformational changes and/or stabilization and thereby provide new means of controlling the properties of β-sheets. Surprisingly, X-ray crystal structures revealed that the introduction of aromatic clusters produced only subtle conformational changes in the OspA β-sheet. Additionally, despite burying a large degree of hydrophobic surface area, the aromatic cluster mutants were slightly less stable than the wild-type scaffold. These results thereby demonstrate that the introduction of aromatic cluster mutations can serve as a means for subtly modulating β-sheet conformation in protein design.
- Department of Biochemistry and Molecular Biology, The University of Chicago, 929 East 57th Street, Chicago, Illinois, 60637.
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