Conformational Study of Isobutenylene Chains in Tandem Claisen Rearrangement Products. Insights from X-ray Crystallography and1H NMR for Salicylideneaniline Derivatives

2002 ◽  
Vol 75 (4) ◽  
pp. 831-839 ◽  
Author(s):  
Hirohiko Houjou ◽  
Seiji Tsuzuki ◽  
Yoshinobu Nagawa ◽  
Kazuhisa Hiratani
1994 ◽  
Vol 59 (9) ◽  
pp. 2565-2569 ◽  
Author(s):  
Maria-Selma Arias ◽  
Yves G. Smeyers ◽  
Maria-Jose Fernandez ◽  
Nadine J. Smeyers ◽  
Enrique Galvez ◽  
...  

1987 ◽  
Vol 28 (45) ◽  
pp. 5565-5568 ◽  
Author(s):  
G.H. Baker ◽  
P.J. Brown ◽  
R.J.J. Dorgan ◽  
J.R. Everett ◽  
S.V. Ley ◽  
...  

Author(s):  
Jules S. Jaffe ◽  
Robert M. Glaeser

Although difference Fourier techniques are standard in X-ray crystallography it has only been very recently that electron crystallographers have been able to take advantage of this method. We have combined a high resolution data set for frozen glucose embedded Purple Membrane (PM) with a data set collected from PM prepared in the frozen hydrated state in order to visualize any differences in structure due to the different methods of preparation. The increased contrast between protein-ice versus protein-glucose may prove to be an advantage of the frozen hydrated technique for visualizing those parts of bacteriorhodopsin that are embedded in glucose. In addition, surface groups of the protein may be disordered in glucose and ordered in the frozen state. The sensitivity of the difference Fourier technique to small changes in structure provides an ideal method for testing this hypothesis.


Author(s):  
S. Cusack ◽  
J.-C. Jésior

Three-dimensional reconstruction techniques using electron microscopy have been principally developed for application to 2-D arrays (i.e. monolayers) of biological molecules and symmetrical single particles (e.g. helical viruses). However many biological molecules that crystallise form multilayered microcrystals which are unsuitable for study by either the standard methods of 3-D reconstruction or, because of their size, by X-ray crystallography. The grid sectioning technique enables a number of different projections of such microcrystals to be obtained in well defined directions (e.g. parallel to crystal axes) and poses the problem of how best these projections can be used to reconstruct the packing and shape of the molecules forming the microcrystal.Given sufficient projections there may be enough information to do a crystallographic reconstruction in Fourier space. We however have considered the situation where only a limited number of projections are available, as for example in the case of catalase platelets where three orthogonal and two diagonal projections have been obtained (Fig. 1).


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