A Genetic Approach for Controlling the Binding and Orientation of Proteins on Nanoparticles
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- 作者：Atanu Sengupta ; Corrine K. Thai ; M. S. R. Sastry ; James F. Matthaei ; Daniel T. Schwartz ; E. James Davis ; Franç ; ois Baneyx
- 刊名：Langmuir
- 出版年：2008
- 出版时间：March 4, 2008
- 年：2008
- 卷：24
- 期：5
- 页码：2000 - 2008
- 全文大小：367K
- 年卷期：v.24,no.5(March 4, 2008)
- ISSN：1520-5827
文摘
Although silver nanoparticles are excellent surface enhancers for Raman spectroscopy, their use to probe theconformation of large proteins at interfaces has been complicated by the fact that many polypeptides adsorb weaklyor with a random orientation to colloidal silver. To address these limitations, we sought to increase binding affinityand control protein orientation by fusing a silver-binding dodecapeptide termed Ag4 to the C-terminus of maltose-binding protein (MBP), a well-characterized model protein with little intrinsic silver binding affinity. Quartz crystalmicrobalance measurements conducted with the MBP-Ag4 fusion protein revealed that its affinity for silver (Kd 
180 nM) was at least 1 order of magnitude higher than a control protein, MBP2, containing a non-silver-specificC-terminal extension. Under our experimental conditions, MBP-Ag4 SERS spectra exhibited 2-4 fold higher signal-to-background relative to MPB2 and contained a number of amino acid-assigned vibrational modes that were eitherweak or absent in control experiments performed with MBP2. Changes in amino acid-assigned peaks before and afterMBP-Ag4 bound maltose were used to assess protein orientation on the surface of silver nanoparticles. The geneticroute described here may prove useful to study the orientation of other proteins on a variety of SERS-active surfaces,to improve biosensors performance, and to control functional nanobiomaterials assembly.
180 nM) was at least 1 order of magnitude higher than a control protein, MBP2, containing a non-silver-specificC-terminal extension. Under our experimental conditions, MBP-Ag4 SERS spectra exhibited 2-4 fold higher signal-to-background relative to MPB2 and contained a number of amino acid-assigned vibrational modes that were eitherweak or absent in control experiments performed with MBP2. Changes in amino acid-assigned peaks before and afterMBP-Ag4 bound maltose were used to assess protein orientation on the surface of silver nanoparticles. The geneticroute described here may prove useful to study the orientation of other proteins on a variety of SERS-active surfaces,to improve biosensors performance, and to control functional nanobiomaterials assembly.