A microscopic electrostatic model for the amphotericin B channel.
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.
Bonilla-Marín
M
M
Depto. de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City.
Moreno-Bello
M
M
Ortega-Blake
I
I
D000666:Amphotericin B / Q000737:chemistry* / Q000378:metabolism; D004553:Electric Conductivity; D007473:Ion Channels / Q000737:chemistry*; D008958:Models, Molecular; D014961:X-Ray Diffraction
D007473:Ion Channels; D000666:Amphotericin B