Nucleobase-Directed Amyloid Nanotube Assembly

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• 作者：Peng Liu ; Rong Ni ; Anil K. Mehta ; W. Seth Childers ; Ami Lakdawala ; Sai Venkatesh Pingali ; Pappannan Thiyagarajan ; David G. Lynn
• 刊名：Journal of the American Chemical Society
• 出版年：2008
• 出版时间：December 17, 2008
• 年：2008
• 卷：130
• 期：50
• 页码：16867-16869
• 全文大小：237K
• 年卷期：v.130,no.50(December 17, 2008)
• ISSN：1520-5126

文摘

Cytosine nucleobases were successfully incorporated into the side chain of the self-assembling amyloid peptide fragment HHQALVFFA to give ccAQLVFFA. At a pH range of 3−4, where cytosine is expected to be partially protonated, small-angle X-ray scattering analyses revealed the nucleobase peptide assembles to be well-defined nanotubes with an outer diameter of 24.8 nm and wall thicknesses of 3.3 nm. FT-IR and X-ray diffraction confirmed β-sheet-rich assembly with the characteristic cross-β architecture of amyloid. The β-sheet registry, determined by measuring <sup>13sup>CO−<sup>13sup>CO backbone distances with solid-state NMR and linear dichroism, placed the cytosine bases roughly perpendicular to the nanotube axis, resulting in a model where the complementary interactions between the cytosine bases increases β-sheet stacking to give the nanotube architecture. These scaffolds then extend the templates used to encode biological information beyond the nucleic acid duplexes and into covalent networks whose self-assembly is still defined by a precise complementarity of the side-chain registry.