Bonilla-Marín M, Moreno-Bello M, Ortega-Blake I
Depto. de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City.
Biochim Biophys Acta. 1991 Jan 9;1061(1):65-77. doi: 10.1016/0005-2736(91)90269-e.
A microscopic model of an amphotericin B channel is proposed. The structure of the pores is generated using the atomic coordinates of the molecule in the structure determined experimentally by X-ray diffraction. The net charges of the atoms are determined by Mulliken analysis. With these charges the electrostatic energy profiles are calculated for a monovalent ion passing through the channels formed by different number of antibiotic molecules having different radii. The water inside the channel was considered through a continuum medium using the dielectric constant of the bulk, and the membrane contribution was included using the virtual images of the pore in a dielectric slab of epsilon = 3. The model satisfactorily explains the permeability and selectivity characteristics as well as other observations yet unexplained. The electrostatic profiles obtained reinforce the hypothesis of the existence of channels formed by a variable number of units.
提出了两性霉素B通道的微观模型。利用X射线衍射实验确定的结构中分子的原子坐标生成孔的结构。通过穆利肯分析确定原子的净电荷。利用这些电荷，计算了单价离子通过由不同数量、不同半径的抗生素分子形成的通道时的静电能分布。通道内的水通过使用本体的介电常数的连续介质来考虑，并且使用ε = 3的电介质板中的孔的虚拟图像来包括膜的贡献。该模型令人满意地解释了渗透性和选择性特征以及其他尚未解释的观察结果。所获得的静电分布强化了由可变数量的单元形成通道的假设。
