Chemist Karen Wetterhahn spilt a drop of dimethylmercury on her gloved hand in 1996 at Dartmouth College in New Hampshire. At the time, it was not known that the chemical passes through latex, so she did not realize it had reached her skin. She fell ill five months later and died within the year.
15/04/2009
Dangers in the lab
It is always good to read about dangers in the lab, and Nature in it's issue of 2 April has a nice feature about it on page 664-665 (subscription necessary). Note the following passage about the dangers of a mercury compound:
Chemist Karen Wetterhahn spilt a drop of dimethylmercury on her gloved hand in 1996 at Dartmouth College in New Hampshire. At the time, it was not known that the chemical passes through latex, so she did not realize it had reached her skin. She fell ill five months later and died within the year.
Chemist Karen Wetterhahn spilt a drop of dimethylmercury on her gloved hand in 1996 at Dartmouth College in New Hampshire. At the time, it was not known that the chemical passes through latex, so she did not realize it had reached her skin. She fell ill five months later and died within the year.
13/04/2009
NMR and crystallography, or rather, crystallography and NMR.
I like the ultimate paragraph of the Highlight written by Burkhard Luy in Angewandte Chemie Int. Ed. (2007, volume 46, pages 4214-4216), it illustrates the complementarity of X-ray crystallography and NMR spectroscopy very well:
"With the NMR techniques developed over the past decade and the availability of corresponding crystal structures, molecular complexes of nearly unlimited size seem to be amenable to liquid-state dynamics measurements. These results are an important step in understanding the modes of operation of complicated molecular machines in biological systems."
Note that the crystal structure of the 20S proteasome complex was necessary in order to be able to interpret the NMR signals of the particle, and that the NMR results shed light on dynamic properties which crystallography had not measured.
Also note the NMR work was expensive, requiring extensive labeling, mutation to make a monomeric version - so it would presumably be only worth doing this for very important macromolecular complexes.
"With the NMR techniques developed over the past decade and the availability of corresponding crystal structures, molecular complexes of nearly unlimited size seem to be amenable to liquid-state dynamics measurements. These results are an important step in understanding the modes of operation of complicated molecular machines in biological systems."
Note that the crystal structure of the 20S proteasome complex was necessary in order to be able to interpret the NMR signals of the particle, and that the NMR results shed light on dynamic properties which crystallography had not measured.
Also note the NMR work was expensive, requiring extensive labeling, mutation to make a monomeric version - so it would presumably be only worth doing this for very important macromolecular complexes.
06/04/2009
Tracing a protein at 5.5 Å resolution
In a paper published in Nature 26 March 2009 (p. 475), Pomeranz Krummel et al. describe the structure of human spliceosomal U1 snRNP at 5.5 Å resolution. what struck me is how they traced the structure of one of the component proteins: via mutating individually all methionine residues of the Se-Met versions of the protein, crystallising and collecting data of all variant complexes and locating the said methionines in anomalous difference maps. A real tour-de-force!
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