Influence of fluctuations in electron density on the excess small-angle X-ray scattering from dilute solutions of macromolecules

✍ Scribed by Dewey K. Carpenter; Wayne L. Mattice

• Publisher: Wiley (John Wiley & Sons)
• Year: 1977
• Tongue: English
• Weight: 581 KB
• Volume: 16
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1977.360160106

✦ Synopsis

The influence on the excess scattering function P ( p ) of fluctuations in the electron density p within a macromolecule is treated, to the approximation that the solvent is a structureless medium of constant electron density po. The results for P ( M ) and the apparent value of the mean square radius R,,,', can be expressed as functions of the excess electron density Ap:

where X ( p ) and R , depend only on the shape of the macromolecule, while Y ( K )

and R, as well as Z(p) and R Z 2 depend on the shape and the fluctuations in p. By varying the electron density of the solvent, the contributions of the shape and the internal structure of the macromolecule can be resolved. The quantities R, 2, RY2, and R, are evaluated for seven models to illustrate the relative importance of these contributions for representative structures.