Using the ring-shaped protein TRAP to capture and confine gold nanodots on a surface

Small. 2007 Nov;3(11):1950-6. doi: 10.1002/smll.200700400.


The cavity of the toroidal protein TRAP (trp RNA-binding attenuation protein) is modified to capture gold nanodots in solution. By engineering a titanium-binding peptide onto one surface of the ring it is also possible to bind it specifically and tightly to a TiO2 surface. TRAP bound in this way is then used to capture gold nanodots and attach them to prepared surfaces. Gold-protein complexes are observed using atomic force microscopy and transmission electron microscopy. The modified TRAP is used to build gold nanodots into the SiO2 layer of a metal oxide semiconductor. This is the first use of a ring protein, rather than the more commonly used spherical protein cages, to constrain nanodots to a surface. This method is an important addition to the current range of bionanotechnology tools and may be the basis for future, multicomponent electronic devices.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / ultrastructure*
  • Binding Sites
  • Crystallization / methods*
  • Gold / chemistry*
  • Macromolecular Substances / chemistry
  • Materials Testing
  • Molecular Conformation
  • Nanospheres / chemistry*
  • Nanospheres / ultrastructure*
  • Nanotechnology / methods*
  • Particle Size
  • Protein Binding
  • RNA-Binding Proteins / chemistry*
  • RNA-Binding Proteins / ultrastructure*
  • Surface Properties
  • Transcription Factors / chemistry*
  • Transcription Factors / ultrastructure*


  • Bacterial Proteins
  • Macromolecular Substances
  • MtrB protein, Bacteria
  • RNA-Binding Proteins
  • Transcription Factors
  • Gold