A measure for the angle between projections based on the extent of correlation between corresponding central sections

Ardan Patwardhan, Danielle Paul, Hind A. AL-Khayat, Edward P. Morris

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

A pre-condition for the ab initio assignment of Euler angles to a set of projections from an asymmetric object is that at least three of the available projections correspond to rotations about different axes. For symmetric objects this condition may be relaxed. There are some applications of single-particle electron microscopy, such as the reconstruction of filamentous macromolecular assemblies, where all available projections more-or-less correspond to rotations about a common rotation axis making it difficult to satisfy this condition. Here, a method has been developed to overcome this problem, based on the fact that the correlation between two central sections of the Fourier transform of a compact object will not be limited to an infinitesimal central line but will have a finite extent, which is related to the angle between the corresponding projections. Projections from model filaments, with different degrees of rotational symmetry about the long axis, have been used to test the methodology. The results show that angle determination is robust down to signal-to-noise ratios as low as 2 and that, in general, the error decreases as the degree of symmetry increases. The method has been used to assign angles to a set of negatively stained muscle thick filament projections to obtain an initial 3D reconstruction. The main features of the projections are seen to be faithfully reproduced in the reprojections from the reconstruction. A real-space adaptation of this method is also discussed.

Original languageEnglish
Pages (from-to)707-724
Number of pages18
JournalJournal of Molecular Biology
Volume344
Issue number3
DOIs
Publication statusPublished - 26 Nov 2004
Externally publishedYes

Fingerprint

Signal-To-Noise Ratio
Fourier Analysis
Electron Microscopy
Muscles

Keywords

  • 3D reconstruction
  • angular reconstitution
  • electron microscopy
  • myosin
  • single particle analysis

ASJC Scopus subject areas

  • Virology

Cite this

A measure for the angle between projections based on the extent of correlation between corresponding central sections. / Patwardhan, Ardan; Paul, Danielle; AL-Khayat, Hind A.; Morris, Edward P.

In: Journal of Molecular Biology, Vol. 344, No. 3, 26.11.2004, p. 707-724.

Research output: Contribution to journalArticle

Patwardhan, Ardan ; Paul, Danielle ; AL-Khayat, Hind A. ; Morris, Edward P. / A measure for the angle between projections based on the extent of correlation between corresponding central sections. In: Journal of Molecular Biology. 2004 ; Vol. 344, No. 3. pp. 707-724.
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