Method for modelling the electron density of a crystal

摘要

A method for modelling the electron density distribution of a macromolecule in a defined asymmetric unit of a crystal lattice having locations of uniformly diffracting electron density includes the steps of: producing an initial distribution of scattering bodies with a asymmetric unit having the same dimensions as the defined asymmetric unit; calculating scattering amplitudes of the initial distribution and determining the correlation between the calculated scattering amplitudes and the normalized amplitudes; moving at least one of the scattering bodies within the asymmetric unit to create a modified distribution; calculating scattering amplitudes and phases of the modified distribution and determining the correlation between the calculated amplitudes and producing a final distribution of scattering bodies by repeating moving and calculating steps until the correlation between the calculated scattering amplitudes and the normalized amplitudes is effectively maximized, the final distribution of scattering bodies defining the electron density of the crystal.