Normal modes as refinement parameters for the F-actin model.

M M Tirion; D ben-Avraham; M Lorenz; K C Holmes

doi:10.1016/s0006-3495(95)80156-6

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Normal modes as refinement parameters for the F-actin model.

M M Tirion·D ben-Avraham·M Lorenz·K C Holmes

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Abstract

The slow normal modes of G-actin were used as structural parameters to refine the F-actin model against 8-A resolution x-ray fiber diffraction data. The slowest frequency normal modes of G-actin pertain to collective rearrangements of domains, motions that are characterized by correlation lengths on the order of the resolution of the fiber diffraction data. Using a small number of normal mode degrees of freedom (< or = 12) improved the fit to the data significantly. The refined model of F-actin shows that the nucleotide binding cleft has narrowed and that the DNase I binding loop has twisted to a lower radius, consistent with other refinement techniques and electron microscopy data. The methodology of a normal mode refinement is described, and the results, as applied to actin, are detailed.

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Actins Algorithms Animals Binding Sites Biophysical Phenomena Biophysics Models, Molecular Molecular Structure Protein Conformation Stereoisomerism X-Ray Diffraction Journal Article Research Support, U.S. Gov't, Non-P.H.S.

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M M Tirion, D ben-Avraham, M Lorenz, K C Holmes. 1995. Normal modes as refinement parameters for the F-actin model.. https://doi.org/10.1016/s0006-3495(95)80156-6

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