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Sequence recombination improves target specificity in a redesigned collagen peptide abc-type heterotrimer

Authors

  • Sumana Giddu,

    1. Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey 08854
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  • Fei Xu,

    1. Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey 08854
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  • Vikas Nanda

    Corresponding author
    1. Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey 08854
    • CABM Room 206, 679 Hoes Lane West, Piscataway, NJ 08854
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Abstract

Stability of the collagen triple helix is largely governed by its imino acid content, namely the occurrence of proline and 4R-hydroxyproline at the X and Y positions, respectively, of the periodic (Gly-X-Y)n sequence. Although other amino acids at these positions reduce stability of the triple helix, this can be partially compensated by introducing intermolecular side-chain salt bridges. This approach was previously used to design an abc-type heterotrimer composed of one basic, one acidic, and one neutral imino acid rich chain (Gauba and Hartgerink, J Am Chem Soc 2007;129:15034–15041). In this study, an abc-type heterotrimer was designed to be the most stable species using a sequence recombination strategy that preserved both the amino acid composition and the network of interchain salt bridges of the original design. The target heterotrimer had the highest Tm of 50°C, 7°C greater than the next most stable species. Stability of the heterotrimer decreased with increasing ionic strength, consistent with the role of intermolecular salt bridges in promoting stability. Quantitative meta-analysis of these results and published stability measurements on closely related peptides was used to discriminate the contributions of backbone propensity and side-chain electrostatics to collagen stability. Proteins 2013. © 2012 Wiley Periodicals, Inc.

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