Title:
Anatomy of a Selectively Coassembled Beta-sheet Peptide Nanofiber Dataset
Anatomy of a Selectively Coassembled Beta-sheet Peptide Nanofiber Dataset
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Author(s)
Shao, Qing
Wong, Kong M.
Seroski, Dillon T.
Wang, Yiming
Liu, Renjie
Paravastu, Anant K.
Hudalla, Gregory A.
Hall, Carol K.
Wong, Kong M.
Seroski, Dillon T.
Wang, Yiming
Liu, Renjie
Paravastu, Anant K.
Hudalla, Gregory A.
Hall, Carol K.
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Abstract
Peptide self-assembly, wherein molecule A associates with other A molecules to form fibrillar β-sheet structures, is common in nature and widely used to fabricate synthetic biomaterials. Selective coassembly of peptide pairs A and B with complementary partial charges is gaining interest due to its potential for expanding the form and function of biomaterials that can be realized. It has been hypothesized that charge-complementary peptides organize into alternating ABAB-type arrangements within assembled β-sheets, but no direct molecular-level evidence exists to support this interpretation. We report a computational and experimental approach to characterize molecular-level organization of the established peptide pair, CATCH. Discontinuous molecular dynamics simulations predict that CATCH(+) and CATCH(−) peptides coassemble but do not self-assemble. Two-layer β-sheet amyloid structures predominate, but off-pathway β-barrel oligomers are also predicted. At low concentration, transmission electron microscopy and dynamic light scattering identified nonfibrillar ∼20-nm oligomers, while at high concentrations elongated fibers predominated. Thioflavin T fluorimetry estimates rapid and near-stoichiometric coassembly of CATCH(+) and CATCH(−) at concentrations ≥100 μM. Natural abundance 13C NMR and isotope-edited Fourier transform infrared spectroscopy indicate that CATCH(+) and CATCH(−) coassemble into two-component nanofibers instead of self-sorting. However, 13C–13C dipolar recoupling solid-state NMR measurements also identify nonnegligible AA and BB interactions among a majority of AB pairs. Collectively, these results demonstrate that strictly alternating arrangements of β-strands predominate in coassembled CATCH structures, but deviations from perfect alternation occur. Off-pathway β-barrel oligomers are also suggested to occur in coassembled β-strand peptide systems.
Sponsor
National Science Foundation Division of Chemical, Bioengineering, Environmental and Transport Systems Grant 1743432
Date Issued
2020-01
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Creative Commons Attribution 4.0 International