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The experimental process of collecting images from macromolecules in an electron microscope is such that it does not allow for prior specification of the angular distribution of the projection images. As a consequence, an uneven distribution of projection directions may occur. Concerns have been raised recently about the behavior of 3D reconstruction(More)
The quaternary structure of Sepia officinalis hemocyanin (Hc) as studied in immunoelectron microscopy with rabbit IgGs and Fab fragments raised against functional units (FU) Soc, Sod, Soe, Sof, Sog, and Soh and fragment Soab. The architecture of immunocomplexes shows that (i) epitopes characteristic of FUs Soc and Sog and of fragment Soab are located in the(More)
Hemocyanins, the respiratory molecules of cephalopod mollusks, are hollow cylinders with five internal arches. Three hemocyanins representative of three orders of cephalopods (Benthoctopus species, Octopoda; Vampyroteuthis infernalis, Vampyromorpha; Sepia officinalis, Sepioidea) were subjected to cryoelectron microscopy and three-dimensional (3D)(More)
Iron-oxidizing bacteria are important actors of the geochemical cycle of iron in modern environments and may have played a key role all over Earth's history. However, in order to better assess that role on the modern and the past Earth, there is a need for better understanding the mechanisms of bacterial iron oxidation and for defining potential(More)
Transmission electron microscopy, as most imaging devices, introduces optical aberrations that in the case of thin specimens are usually modeled in Fourier space by the so-called contrast transfer function (CTF). Accurate determination of the CTF is crucial for its posterior correction. Furthermore, the CTF estimation must be fast and robust if(More)
In a context of automation of cryo-electron microscopy, we developed a novel method for improving visibility of diffraction rings in the power spectra of cryo-electron micrographs of vitreous ice (without carbon film or high concentration of diffracting material). We used these enhanced spectra to semi-automatically detect and remove micrographs and/or(More)
Time-resolved small-angle X-ray and neutron scattering (SAXS and SANS) in solution were used to study the swelling reaction of TBSV upon chelation of its constituent calcium at mildly basic pH. SAXS intensities comprise contribution from the protein capsid and the RNA moiety, while neutron scattering, recorded in 72% D2O, is essentially due to the protein(More)
The extracellular respiratory pigment of the cuttlefish Sepia officinalis was observed by cryoelectron microscopy with conventional LaB(6) and field emission gun electron sources at 100 and 200 kV, respectively. Each image series was used to compute one 3D reconstruction volume with correction of the contrast transfer function by Wiener filtering. A strong(More)
The three-dimensional (3D) reconstructions of the di-decameric forms of alpha D and beta C-hemocyanins of the Roman snail Helix pomatia and of the decameric half molecules of alpha D-hemocyanin were carried out on frozen-hydrated specimens observed in the electron microscope by using the random conical tilt series method. The three 3D volumes were examined(More)
A frozen-hydrated sample of Octopus vulgaris hemocyanin was imaged at 0 degree and 40 degrees tilt angle under low dose conditions by transmission electron microscopy. A three-dimensional reconstruction by the method of random conical tilt series produced a three-dimensional volume to which a D5 symmetry was applied. Examination of serial sections in the(More)