EMBL Hamburg Biological
Small Angle Scattering

Ab initio methods: how they work

Dmitri Svergun

EMBL Hamburg, Germany

Principles of ab initio shape determination in small-angle scattering are explained and different approached proposed to reconstruct three-dimensional models out of one-dimensional scattering data are presented. The question of informational content in the small-angle scattering data is related to the possibility of ab initio shape analysis. Several methods are discussed including the angular envelope function based on spherical harmonics (Stuhrmann, 1970; Svergun & Stuhrmann, 1991; Svergun et al., 1996), and Monte-Carlo type approaches using models consisting of densely packed fixed beads (Chacon et al., 1998; Svergun, 1999; Walther, Cohen & Doniach, 2000) or condensation of a gas of dummy residues (Svergun, Petoukhov & Koch, 2001). The possibilities (and necessity) of the use of a priori information are discussed and advantages and limitations of ab initio methods are illustrated in practical applications.

Models used in ab initio methods

Envelope function, Bead models, Dummy residues model
All the methods minimize Discrepancy[Data] + Penalty[Additional info]


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Date/time: Wednesday, 29 October 2014, 9:00

  Last modified: October 16, 2014

© BioSAXS group 2014