実験報告書様式（一般利用課題・成果公開利用）（ ※本報告書は英語で記述してください。ただし、産業利用課題として採択されている方は日本語で記述していただいても結構です。 ）MLF Experimental Report
課題番号 Project No. 2017B0130

提出日 Date of Report
装置責任者 Name of responsible person
Hiroki Iwase

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Investigation of specific protein aggregation depended on

Taikan/BL15

meso-cavity sizes

実施日 Date of Experiment

実験責任者名 Name of principal investigator

11-15/Dec/2017

Akira Yamaguchi
所属 Affiliation
Ibaraki University
試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.
Mesoporous silica (SiO2) powder dispersed in D2O/H2O mixtures.
Myoglobin in D2O/H2O mixtures.
Mesoporous silica containing myoglobin dispersed in D2O/H2O mixtures.

2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results.

If you failed to conduct experiment as planned, please describe reasons.

SANS experiments for above samples were performed by TAIKAN. The mesoporous silica is oneof inoragnic nanoporous material with uniform pore structure. The main purpose of our research isobservation of myoglobin (Mb) molecules confined inside the pore of mesoporous silica bycontrast-variation SANS experiments. Until now, we have performed SANS experiments for Mb withinmesoporous silica. The main purpose of this project is to obtain reliable SANS profiles to analyze theMb tertiary structure depended on the pore size. In addition, the possibility of the specific molecularaggregation of Mb was examined.
Result 1: SANS experiments for Mb within mesoporous silica (62.1% D2O)
Herein, we prepared mesoporous silica powders with different pore sizes. The conjugates ofmesoporous silica (MPS) and Mb (Mb/MPS conjugate) were dispersed in the contrast-matching solvent(62.1% D2O), and the slurry samples were applied for SANS experiments.
12. 実験方法及び結果（つづき） Experimental method and results (continued)
In the present study, we prepared a series of Mb/MPS conjugates with different MPS pore sizes.
The measurement time for each slurry samples was 8 to 10 h to obtain reliable scattering signal due tothe Mb within MPS.
As the results, we obtained scattering data for Mb without interference of MPS. The scattering data
could be well fitted to hard-sphere model, and the radius of Mb within MPS obtained by the fitting
analysis was well agreed with that of free Mb in bulk D2O. This result indicates that the tertiary
structure of Mb is almost same with that of free Mb with spherical structure.
On the other hand, SANS profile of Mb within specific MPS sample was not well fitted to thehard-sphere model. From other spectroscopic studies, complete unfolding of Mb within the specific
MPS was ruled out. We hence analyzed the SANS profile by other models (ellipsoidal and core-shellmodels). As the results, it was concluded that partial unfolding of Mb took place within the specific
MPS pores.

In addition, it was also concluded that the pore size did not affect the Mb tertiary

structure.
Article containing above results is now preparing.
Result 2: Specific Mb assembly within mesoporous silica
Herein, we also found specific Mb assembly within MPS with specific pore sizes. This specific Mb
assembly could be explained by the results in previous SANS study.

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