Further Electron Microscope Studies on Pyruvate Carboxylase
| Autor: | Frank Mayer, John C. Wallace, D. Bruce Keech |
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| Rok vydání: | 1980 |
| Předmět: |
Models
Molecular Macromolecular Substances Protein Conformation Protein subunit Mitochondria Liver Biology Biochemistry law.invention 03 medical and health sciences Species Specificity Acetyl Coenzyme A law Animals Molecule Electron microscopic Pyruvate Carboxylase 030304 developmental biology 0303 health sciences Sheep Rhomboid 030302 biochemistry & molecular biology Negative stain Rats Pyruvate carboxylase Microscopy Electron Crystallography Liver Acetylcoenzyme A Electron microscope Chickens |
| Zdroj: | European Journal of Biochemistry. 112:265-272 |
| ISSN: | 1432-1033 0014-2956 |
| DOI: | 10.1111/j.1432-1033.1980.tb07202.x |
| Popis: | Using negative staining and electron microscopic tilting techniques in conjunction with modelling experiments, the fine structure of chicken, sheep and rat pyruvate carboxylases has been studied. The overall configuration appears to be a tetrahedron-like structure consisting of two pairs of subunits in two different planes orthogonal to each other with the opposing pairs of subunits interacting with each other on their convex surfaces. The predominant form of the enzyme particles mounted and stained in the presence of acetylcoenzyme A consisted of a compact, triangular outline enclosing three readily visible intensity maxima. When samples were mounted in the absence of acetyl-coenzyme A the molecules were more ‘open’ predominantly rhomboid structures. From tilting experiments it is concluded that the rhomboid images found in the absence of acetyl-coenzyme A represent partly or wholly flattened forms of the tetrahedron-like molecule. A feature of the enzyme when mounted in the absence of acetyl-coenzyme A was the existence of a ‘cleft’ along the longitudinal midline of each subunit, suggesting that the subunits may consist of two distinct domains. |
| Databáze: | OpenAIRE |
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