Session: PMSE/POLY Poster Session:

Peptide coassembly expands the architectural space for engineering functional biomaterials for medical and biotechnological applications. Coassembling peptides are designed to resist self-assembly in single-peptide solutions but form two-component nanofibers upon mixing. Most existing peptide pairs utilize electrostatic interactions to discourage self-assembly among like-charged peptides and to promote coassembly behavior between oppositely charged peptides. These charge-complementary molecules should ideally form coassembled antiparallel β-sheets with perfect alternation of positively and negatively charged β-strands (i.e. (AB)_n patterning). We characterize the molecular level structure for two known coassembling systems, King-Webb peptides and CATCH peptides, using solid-state NMR spectroscopy and discontinuous molecular dynamics (DMD) simulations. Experimental and computational results indicate a significant deviation from an ideal nanofiber structure; molecules have some like-peptide neighbors and parallel-oriented neighbors. DMD simulations also predict out-of-register β-strands. Differences between the King-Webb amino acid sequences and the CATCH amino acid sequences may rationalize differences structural heterogeneity observed between the two coassembling systems. nanofiber structure. Finally, we assess the role of overall molecular charge on selecting peptide coassembly over self-assembly to form perfectly alternating binary β-sheets.

Qing Shao

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