TY - JOUR
T1 - Surface differentiation of ferritin and apoferritin with atomic force microscopic techniques
AU - Ho, Ru Hung
AU - Chen, Yu Hung
AU - Wang, Chong Mou
N1 - Funding Information:
We acknowledge financial support from the National Science Council, Republic of China (grant number: 99-2113-M-003-008-MY3 ).
PY - 2012/6/1
Y1 - 2012/6/1
N2 - In the study reported herein, we differentiated the structure of ferritin from that of its demetalated counterpart, apoferritin, using field-effect-based atomic force microscopic (AFM) techniques. When ferritin was subjected to conductive-mode AFM analysis, the protein resembled a pancake with a diameter of 10. nm adsorbed on the indium-doped tin-oxide substrate with its fourfold channel perpendicular to the substrate, whereas a flat, empty cavity was revealed for apoferritin. We also attempted to verify the conformational difference with magnetic-mode AFM. However, the resulting phase images failed to differentiate the proteins due to interference from the fringe effect. Despite this, the ferritin analysis revealed a sound correlation between the surface conductivity profiles and the phase profiles. In contrast, apoferritin showed a chaotic relationship in this respect. These results not only suggest that the magnetic domain of ferritin is limited to the iron aggregate in the core, but also demonstrate that AFM is a useful tool for protein conformation analysis.
AB - In the study reported herein, we differentiated the structure of ferritin from that of its demetalated counterpart, apoferritin, using field-effect-based atomic force microscopic (AFM) techniques. When ferritin was subjected to conductive-mode AFM analysis, the protein resembled a pancake with a diameter of 10. nm adsorbed on the indium-doped tin-oxide substrate with its fourfold channel perpendicular to the substrate, whereas a flat, empty cavity was revealed for apoferritin. We also attempted to verify the conformational difference with magnetic-mode AFM. However, the resulting phase images failed to differentiate the proteins due to interference from the fringe effect. Despite this, the ferritin analysis revealed a sound correlation between the surface conductivity profiles and the phase profiles. In contrast, apoferritin showed a chaotic relationship in this respect. These results not only suggest that the magnetic domain of ferritin is limited to the iron aggregate in the core, but also demonstrate that AFM is a useful tool for protein conformation analysis.
KW - Atomic force microscopy
KW - Ferritin
KW - Protein conformation analysis
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U2 - 10.1016/j.colsurfb.2012.01.044
DO - 10.1016/j.colsurfb.2012.01.044
M3 - Article
C2 - 22377219
AN - SCOPUS:84862780407
SN - 0927-7765
VL - 94
SP - 231
EP - 235
JO - Colloids and Surfaces B: Biointerfaces
JF - Colloids and Surfaces B: Biointerfaces
ER -