2006 Fiscal Year Final Research Report Summary
Orientation control of protein crystals nucleated on nano-patterned organic substrates
| Project/Area Number |
17560016
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | Ritsumeikan University |
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Principal Investigator |
NAKADA Toshitaka Ritsumeikan Univ., Faculty of Science and Engineering, Professor, 理工学部, 教授 (20237308)
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| Co-Investigator(Kenkyū-buntansha) |
HONDOH Hironori Ritsumeikan Univ., Faculty of Science and Engineering, Lecturer, 理工学部, 講師 (10368003)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Protein / Crystal Growth / Orientation control / Epitaxy / Organic substrate |
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| Research Abstract |
We have carried out the crystallization of lysozyme on organic thin films that have well defined surface microstructures. In order to reveal the nucleation mechanism of oriented lysozyme crystals, effects of the structure of the films and the composition of crystallization solutions were investigated systematically. Some of our findings are summarized as follows ;
(1) We successfully demonstrated the epitaxial growth of lysozyme molecules on fatty acid monolayer films. The c-axes of the {110}-oriented lysozyme crystals nucleated on the stearic acid and behenic acid thin films are oriented with respect to the three directions corresponding to the six-fold symmetry of the mica surface. On the other hand, almost no {110}-oriented lysozyme crystals were observed on the monolayer film formed from myristic acid.These results indicate that monolayer films of fatty acid molecules with an appropriate carbon chain length, promote the epitaxial growth of lysozyme.
(2) We have performed ATR/FT-IR measurements of protein adsorption processes on solid surface. By using deconvolution of the FT-IR spectra, we successfully established the methods to analyze the coverage of the adsorbed proteins, orientation of the protein molecules and their denaturation.
(3) We examined some new combination of the crystals and template substrates, such as CaCO_3 / behenic acids. In the case of CaCO3 crystals nucleated on fatty acid thin films, the behenic acid islands remarkably promoted the nucleation of calcite. In contrast, the nucleation of aragonite crystals was almost independent of the presence of the behenic acid islands. Structural changes of the behenic acid islands in superpure water suggest that the carboxyl groups exposed on the island surface are the nucleation cite of the calcite crystals.
Although the theoretical analyses of these results are now in progress, we believe that the macro-bond analysis of protein will be quite useful on them.
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