Volume 21, Issue 1-2 p. 74-79
Communication

Self-Assembly of Proteinaceous Shells around Positively Charged Gold Nanomaterials Enhances Colloidal Stability in High-Ionic-Strength Buffers

Dr. Eita Sasaki

Dr. Eita Sasaki

Laboratory of Organic Chemistry, ETH Zürich, Vladimir-Prelog-Weg, 1-5/10, 8093 Zürich, Switzerland

Present address: Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113–8657 Japan

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Ryan M. Dragoman

Ryan M. Dragoman

Laboratory of Inorganic Chemistry, ETH Zürich, Vladimir-Prelog-Weg, 1-5/10, 8093 Zürich, Switzerland

Empa-Swiss Federal Laboratories for Materials Science and Technology, Überland Strasse 129, 8600 Dübendorf, Switzerland

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Dr. Shiksha Mantri

Dr. Shiksha Mantri

Laboratory of Organic Chemistry, ETH Zürich, Vladimir-Prelog-Weg, 1-5/10, 8093 Zürich, Switzerland

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Dr. Dmitry N. Dirin

Dr. Dmitry N. Dirin

Laboratory of Inorganic Chemistry, ETH Zürich, Vladimir-Prelog-Weg, 1-5/10, 8093 Zürich, Switzerland

Empa-Swiss Federal Laboratories for Materials Science and Technology, Überland Strasse 129, 8600 Dübendorf, Switzerland

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Prof. Dr. Maksym V. Kovalenko

Prof. Dr. Maksym V. Kovalenko

Laboratory of Inorganic Chemistry, ETH Zürich, Vladimir-Prelog-Weg, 1-5/10, 8093 Zürich, Switzerland

Empa-Swiss Federal Laboratories for Materials Science and Technology, Überland Strasse 129, 8600 Dübendorf, Switzerland

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Prof. Dr. Donald Hilvert

Corresponding Author

Prof. Dr. Donald Hilvert

Laboratory of Organic Chemistry, ETH Zürich, Vladimir-Prelog-Weg, 1-5/10, 8093 Zürich, Switzerland

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First published: 15 September 2019
Citations: 11

Graphical Abstract

Engineered electrostatic interactions enable the self-assembly of a lumazine synthase variant on differently sized and shaped gold nanomaterials. The resulting complexes possess dramatically enhanced colloidal stability in high-ionic-strength buffers owing to the formation of a protective ≈4-nm-thick proteinaceous shell around the core particle.

Abstract

The enzyme lumazine synthase (LS) has been engineered to self-assemble into hollow-shell structures that encapsulate unnatural cargo proteins through complementary electrostatic interactions. Herein, we show that a negatively supercharged LS variant can also form organic–inorganic hybrids with gold nanomaterials. Simple mixing of LS pentamers with positively charged gold nanocrystals in aqueous buffer spontaneously affords protein-shelled gold cores. The procedure works well with differently sized and shaped gold nanocrystals, and the resulting shelled complexes exhibit dramatically enhanced colloidal stability over a wide range of pH (4.0–10.0) and at high ionic strength (up to 1 m NaCl). They are even stable over days upon dilution in buffer. Self-assembly of engineered LS shells in this way offers an easy and attractive alternative to commonly used ligand-exchange methods for stabilizing inorganic nanomaterials.