Nonequilibrium Synthesis and Assembly of Hybrid Inorganic−Protein Nanostructures Using an Engineered DNA Binding Protein
We show that a protein with no intrinsic inorganic synthesis activity can be endowed with the ability to control the formation of inorganic nanostructures under thermodynamically unfavorable (nonequilibrium) conditions, reproducing a key feature of biological hard-tissue growth and assembly. The non...
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Published in | Journal of the American Chemical Society Vol. 127; no. 44; pp. 15637 - 15643 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
Washington, DC
American Chemical Society
09.11.2005
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Subjects | |
Online Access | Get full text |
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Summary: | We show that a protein with no intrinsic inorganic synthesis activity can be endowed with the ability to control the formation of inorganic nanostructures under thermodynamically unfavorable (nonequilibrium) conditions, reproducing a key feature of biological hard-tissue growth and assembly. The nonequilibrium synthesis of Cu2O nanoparticles is accomplished using an engineered derivative of the DNA-binding protein TraI in a room-temperature precursor electrolyte. The functional TraI derivative (TraIi1753::CN225) is engineered to possess a cysteine-constrained 12-residue Cu2O binding sequence, designated CN225, that is inserted into a permissive site in TraI. When TraIi1753::CN225 is included in the precursor electrolyte, stable Cu2O nanoparticles form, even though the concentrations of [Cu+] and [OH-] are at 5% of the solubility product (K sp,Cu 2 O). Negative control experiments verify that Cu2O formation is controlled by inclusion of the CN225 binding sequence. Transmission electron microscopy and electron diffraction reveal a core−shell structure for the nonequilibrium nanoparticles: a 2 nm Cu2O core is surrounded by an adsorbed protein shell. Quantitative protein adsorption studies show that the unexpected stability of Cu2O is imparted by the nanomolar surface binding affinity of TraIi1753::CN225 for Cu2O (K d = 1.2 × 10-8 M), which provides favorable interfacial energetics (−45 kJ/mol) for the core−shell configuration. The protein shell retains the DNA-binding traits of TraI, as evidenced by the spontaneous organization of nanoparticles onto circular double-stranded DNA. |
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Bibliography: | istex:B8AC33F1CD640A71E9939A4F9DFB0EEE37CC1423 ark:/67375/TPS-5SZCZP6J-G ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0002-7863 1520-5126 |
DOI: | 10.1021/ja055499h |