Three-dimensional structure of bovine NADH:Ubiquinone oxidoreductase of the mitochondrial respiratory chain

A New Generation of the IMAGIC Image Processing System

“…Crystallographic averaging taking imperfections of the crystal into account by ''unbending'' was one of the first options to be implemented in the IMAGIC system (Van Heel and Hollenberg, 1980). Conventional correlation averaging (Saxton and Baumeister, 1982) can now be used to generate 3D reconstructions of 2D crystallographic specimens (Boekema et al, 1984;Schultz et al, 1993). These procedures, including transferfunction correction, were used to find 2D projection images of porin to ∼4 Å resolution (Saß et al, 1989).…”

Helical Packing of Needles from Functionally Altered Shigella Type III Secretion Systems

“…This asymmetry probably results from uneven staining, which is a known artefact of negative staining. 16,17 It cannot result from out of plane tilt, since the layer-line peak(s) in all the powerspectra corresponding to the 1-start helix are well separated from the meridian and at constant positions (data not shown). These peaks, even when of uneven intensity, would be expected to merge at the meridian at a tilt of 58 and disappear entirely at a tilt in excess of 108.…”

Structural studies on mitochondrial NADH dehydrogenase using chemical cross-linking

“…Analysis of the structure of such a complicated enzyme is necessarily at a primitive stage. The overall shape and dimensions of the Neurospora crassa enzyme are known from analysis of twodimensional crystals [11], and a fragment of the bovine heart enzyme has been studied in the same way [12,13]. At the present level of resolution, individual subunits cannot be distinguished, and structure prediction based on primary sequence data, even where available [1], is of limited value in an oligomeric enzyme of such complexity.…”