Electron microscopy of the Mo-Fe-protein from Azotobacter vinelandii nitrogenase.
The quaternary structure of the Mo-Fe-protein from Azotobacter vinelandii has been studied by electron microscopy. A model of the molecule of the Mo-Fe-protein has been proposed: two alpha subunits are displaced relative to two beta subunits along a twofold axis, so the molecule can be characterized by the point-group pseudosymmetry 222. Computer averaging of the images showed that one of the projections of the molecule could be characterized by twofold rotational symmetry. Micrographs of nitrogenase recombined complex (Mo-Fe-protein + Fe-protein) have been obtained. They showed particles close in size and form to the Mo-Fe-protein molecule. Therefore, it has been proposed that the Fe-protein could be situated in the central cavity of Mo-Fe-protein.
D001395:Azotobacter / Q000201:enzymology*; D055598:Chemical Phenomena; D002621:Chemistry; D003201:Computers; D005288:Ferredoxins / Q000302:isolation & purification*; D007089:Image Enhancement / Q000379:methods; D046911:Macromolecular Substances; D008854:Microscopy, Electron; D008983:Molybdoferredoxin / Q000302:isolation & purification*; D009591:Nitrogenase / Q000302:isolation & purification*; D010316:Particle Size
D005288:Ferredoxins; D046911:Macromolecular Substances; D008983:Molybdoferredoxin; D009591:Nitrogenase