Institute of Quantum Beam Science, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, Japan.
Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), Tokai, Ibaraki 319-1106, Japan.
J Phys Chem Lett. 2022 Sep 22;13(37):8684-8691. doi: 10.1021/acs.jpclett.2c01708. Epub 2022 Sep 12.
The condensation of globular myoglobin (Mb) at the pore entrances of mesoporous silica (MPS) with a series of pore diameters (4.2, 6.4, 7.7, and 9.0 nm) was examined by differential scanning calorimetry (DSC) and contrast-matching small-angle neutron scattering (CM-SANS) experiments. The DSC measurements were performed to estimate the amount of Mb adsorbed at two different adsorption sites, namely, the pore interior and the pore entrance regions. The CM-SANS measurements were conducted to observe condensation of Mb molecules at the pore entrance regions. Notably, the nanopore entrance with a diameter close to twice that of the Mb diameter was found to be the specific cavity to facilitate the condensation of globular Mb. The Mb condensation occurred at the entrances of the 6.4 nm pore during the adsorption uptake from concentrated Mb solutions, whereas the adsorption uptake from diluted Mb solutions induced the condensation of Mb at the entrances of the 7.7 nm pore.
采用差示扫描量热法（DSC）和对比匹配小角中子散射（CM-SANS）实验研究了一系列孔径（4.2、6.4、7.7 和 9.0nm）的介孔硅（MPS）中球形肌红蛋白（Mb）在孔口的凝聚。DSC 测量用于估计 Mb 在两个不同吸附位的吸附量，即孔内和孔口区域。CM-SANS 测量用于观察 Mb 分子在孔口区域的凝聚。值得注意的是，发现直径接近 Mb 直径两倍的纳米孔入口是促进球状 Mb 凝聚的特定腔。在从浓缩 Mb 溶液中进行吸附时，Mb 的凝聚发生在 6.4nm 孔的入口处，而从稀释的 Mb 溶液中进行吸附则导致 Mb 在 7.7nm 孔的入口处发生凝聚。
