Noncontact Atomic Force Microscopy - Yale School of Engineering ...

Molecular Resolution Investigation of Lysozyme Crystal
in Liquid by Frequency-Modulation AFM
P.II-13
K. Nagashima 1,2 , M. Abe 1,2 , S. Morita 1,2 , N. Oyabu 2,3 , K. Kobayashi 2,3,4 , H. Yamada 2,3 ,
R. Murai 1 , H. Adachi 1,5 , K. Takano 1,5 , H. Matsumura 1,5 , S. Murakami 5,6 , T. Inoue 1,5 , Y.
Mori 1,5 , M. Ohta 2,7 , R. Kokawa 2,7
1Grad. School of Eng., Osaka Univ.; 2 SENTAN, JST; 3 Electronic Sci. & Eng., Kyoto Univ.; 4 Innovative
Collaboration Center, Kyoto Univ.; 5 SOSHO Inc.; 6 Grad. School of Biosci. and Biotech., Tokyo Insti. of
Tech.; 7 Shimadzu Corporation
Recently, Frequency-Modulation AFM (FM-AFM) in liquids has opened a new
way to direct visualization with atomic or molecular resolution [1,2]. We have developed
a high-resolution FM-AFM working in liquids based on a commercially available AFM
(Shimadzu: SPM-9600), which obtained atomic or molecular resolution in liquid [3].
We have tried to observe protein crystals in liquid. To make high quality protein
crystals is very important for determining its molecular structure by X-ray diffraction
analysis. We observed (110) face of tetragonal lysozyme crystal in saturated solution. A
surface unit cell (11.2 x 3.8 nm) consists of 4 molecules with different orientations from
one another (Fig. 1a). We observed it for the first time at molecular resolution (Fig. 1b),
which was not achieved in contact mode AFM [4]. In addition, we also succeeded to
observe changes of the terrace with admolecule and the point defect when the terrace was
covered with a single unit layer (height = 5.6 nm) in supersaturated solution. Such
observations are considered to be fruitful technique for investigating growth mechanism
at molecular level.
a) b)
c c
5 nm
Figure 1: (a) The molecular-packing arrangement of the tetragonal lysozyme (110) face. The
surface unit cell shows black rectangle. (b) FM-AFM image of tetragonal lysozyme (110) face.
[1] T. Fukuma, K. Kobayashi, K. Matsushige, H. Yamada, Appl. Phys. Lett. 86 (2005) 193108.
[2] T. Fukuma, K. Kobayashi, K. Matsushige, H. Yamada, Appl. Phys. Lett. 87 (2005) 34101.
[3] S. Rode, N. Oyabu, K. Kobayashi, H. Yamada, A. Kuhnle, Langmuir 25 (2009) 2850.
[4] H. Li, M. A. Perozzo, J. H. Konnert, A. Nadarajaha, M. L. Pusey, Acta Cryst. D55 (1999) 1023.
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