Abstract
Single crystals of d-ribulose-1,5-diphosphate carboxylase from tobacco leaves, Nicotiana tabacum (variety Turkish Samsun), have been examined by X-ray diffraction, electron microscopy, and optical diffraction. Twelve molecules are loosely packed into a body-centered cubic unit cell, space group 14132 with cell dimension a = 383 Å. The asymmetric unit is one quarter of a molecule, and the minimum molecular symmetry is 222. This symmetry when combined with estimates of the two subunit masses and stoichiometry is compatible with a molecular structure of the composition L8S8 (L is large subunit, S is small). If all bonds between large and small subunits are equivalent, the true molecular symmetry is 422; this symmetry is consistent with molecular images in micrographs.
Publication types
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Carboxy-Lyases*
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Crystallization
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Crystallography
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Lasers
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Microscopy, Electron
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Nicotiana / enzymology
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Optics and Photonics
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Plants / enzymology
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Plants, Toxic
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Protein Conformation
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Ribulose-Bisphosphate Carboxylase*
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X-Ray Diffraction
Substances
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Carboxy-Lyases
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Ribulose-Bisphosphate Carboxylase