The UKB prescription and the heavy atom effects on the nuclear magnetic shielding of vicinal heavy atoms

2009 ◽  
Vol 11 (27) ◽  
pp. 5615 ◽  
Author(s):  
Alejandro F. Maldonado ◽  
Gustavo A. Aucar
Keyword(s):  
Heavy Atom ◽  
Magnetic Shielding ◽  
Heavy Atoms ◽  
Nuclear Magnetic

A Base Specific Single Heavy Atom Stain for Electron Microscopy

1972 ◽  
Vol 30 ◽  
pp. 184-185
Author(s):  
J. P. Langmore ◽  
N. R. Cozzarelli ◽  
A. V. Crewe
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
High Resolution ◽  
Elastic Scattering ◽  
Heavy Atom ◽  
High Vacuum ◽  
Heavy Atoms ◽  
Large Movement ◽  
Base Sequencing ◽  
Scanning Electron

A system has been developed to allow highly specific derivatization of the thymine bases of DNA with mercurial compounds wich should be visible in the high resolution scanning electron microscope. Three problems must be completely solved before this staining system will be useful for base sequencing by electron microscopy: 1) the staining must be shown to be highly specific for one base, 2) the stained DNA must remain intact in a high vacuum on a thin support film suitable for microscopy, 3) the arrangement of heavy atoms on the DNA must be determined by the elastic scattering of electrons in the microscope without loss or large movement of heavy atoms.

The crystal structure of myoglobin. VI. Seal myoglobin

1960 ◽  
Vol 258 (1293) ◽  
pp. 181-201 ◽  
Keyword(s):  
Tertiary Structure ◽  
Heavy Atom ◽  
Three Dimensional ◽  
Sperm Whale ◽  
Fourier Synthesis ◽  
Heavy Atoms ◽  
Isomorphous Replacement ◽  
Unit Cells ◽  
The Common ◽  
Sperm Whale Myoglobin

Myoglobin from the common seal ( Phoca vitulina ) when crystallized from ammonium sulphate forms monoclinic crystals with space group the unit cell, a = 57·9Å, b = 29·6Å, c = 106·4Å, β = 102°15', contains four molecules. The method of isomorphous replacement has been used in an investigation of the centrosymmetric b -axis projection in which it has been possible to determine signs for nearly all the h0l reflexions having spacings greater than 4Å. Three independent heavy-atom derivatives were employed and the signs so determined have been used to compute a map of the electron density projected on the (010) plane. This projection has been interpreted in terms of the molecule of sperm-whale myoglobin, as deduced by Bodo, Dintzis, Kendrew & Wyckoff (1959) from a three-dimensional Fourier synthesis to 6Å resolution. The results of the interpretation show that the two myoglobin molecules are very similar in form (tertiary structure) in spite of the differences in their amino-acid composition. The relative orientation of the two unit cells with respect to the myoglobin molecule is given and a comparison is made of the positions of the heavy atoms in each molecule.

Nuclear Magnetic Shielding in F2

1969 ◽  
Vol 50 (7) ◽  
pp. 2839-2841 ◽  
Author(s):  
David K. Hindermann ◽  
Lesley L. Williams
Keyword(s):  
Magnetic Shielding ◽  
Nuclear Magnetic

scholarly journals The nuclear magnetic shielding and spin-rotation constants of the hydrogen molecule

1995 ◽  
Vol 236 (1-2) ◽  
pp. 19-23 ◽  
Author(s):  
Jacek Komasa ◽  
Jacek Rychlewski ◽  
William T. Raynes
Keyword(s):  
Hydrogen Molecule ◽  
Spin Rotation ◽  
Magnetic Shielding ◽  
Nuclear Magnetic

scholarly journals The magic triangle goes MAD: experimental phasing with a bromine derivative

2010 ◽  
Vol 66 (4) ◽  
pp. 374-380 ◽  
Author(s):  
Tobias Beck ◽  
Tim Gruene ◽  
George M. Sheldrick
Keyword(s):  
Functional Groups ◽  
Heavy Atom ◽  
Anomalous Dispersion ◽  
Proteinase K ◽  
Nonspecific Binding ◽  
Heavy Atoms ◽  
Carboxylate Groups ◽  
Experimental Phasing ◽  
Sad Phasing ◽  
Bromine Derivative

Experimental phasing is an essential technique for the solution of macromolecular structures. Since many heavy-atom ion soaks suffer from nonspecific binding, a novel class of compounds has been developed that combines heavy atoms with functional groups for binding to proteins. The phasing tool 5-amino-2,4,6-tribromoisophthalic acid (B3C) contains three functional groups (two carboxylate groups and one amino group) that interact with proteinsviahydrogen bonds. Three Br atoms suitable for anomalous dispersion phasing are arranged in an equilateral triangle and are thus readily identified in the heavy-atom substructure. B3C was incorporated into proteinase K and a multiwavelength anomalous dispersion (MAD) experiment at the Br Kedge was successfully carried out. Radiation damage to the bromine–carbon bond was investigated. A comparison with the phasing tool I3C that contains three I atoms for single-wavelength anomalous dispersion (SAD) phasing was also carried out.

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