scholarly journals Self-assembled supramolecular cages containing ruthenium(ii) polypyridyl complexes

2015 ◽  
Vol 51 (21) ◽  
pp. 4465-4468 ◽  
Author(s):  
Jiajia Yang ◽  
Mohan Bhadbhade ◽  
William A. Donald ◽  
Hasti Iranmanesh ◽  
Evan G. Moore ◽  
...  

Substitution-inert, redox- and photo-active ruthenium(ii) complexes based on 2,2′,6′,2′′-terpyridine ligands were self-assembled into discrete supramolecular cages via coordination to palladium(ii) centres and characterised by NMR, ESI-MS and X-ray crystallography.

2019 ◽  
Vol 55 (43) ◽  
pp. 6066-6069 ◽  
Author(s):  
Yoshiteru Kawakami ◽  
Tsuyoshi Ogishima ◽  
Tomoki Kawara ◽  
Shota Yamauchi ◽  
Kazuhiko Okamoto ◽  
...  

Shape-persistent macrocycles and 3D nanocages have been prepared in one-pot under MeCN-promoted dynamic covalent bond conditions starting from silane catecholates, whose structures were confirmed by X-ray crystallography.


2012 ◽  
Vol 312 ◽  
pp. 70-77 ◽  
Author(s):  
Jingshu Guo ◽  
Saurav Uppal ◽  
Lindsey M. Easthon ◽  
Timothy C. Mueser ◽  
Wendell P. Griffith

2014 ◽  
Vol 70 (8) ◽  
pp. 2217-2231 ◽  
Author(s):  
Philippe Bénas ◽  
Nicolas Auzeil ◽  
Laurent Legrand ◽  
Franck Brachet ◽  
Anne Regazzetti ◽  
...  

The adsorption of Rb+, Cs+, Mn2+, Co2+and Yb3+onto the positively charged hen egg-white lysozyme (HEWL) has been investigated by solving 13 X-ray structures of HEWL crystallized with their chlorides and by applying electrospray ionization mass spectrometry (ESI-MS) first to dissolved protein crystals and then to the protein in buffered salt solutions. The number of bound cations follows the order Cs+< Mn2+≃ Co2+< Yb3+at 293 K. HEWL binds less Rb+(qtot= 0.7) than Cs+(qtot= 3.9) at 100 K. Crystal flash-cooling drastically increases the binding of Cs+, but poorly affects that of Yb3+, suggesting different interactions. The addition of glycerol increases the number of bound Yb3+cations, but only slightly increases that of Rb+. HEWL titrations with the same chlorides, followed by ESI-MS analysis, show that only about 10% of HEWL binds Cs+and about 40% binds 1–2 Yb3+cations, while the highest binding reaches 60–70% for protein binding 1–3 Mn2+or Co2+cations. The binding sites identified by X-ray crystallography show that the monovalent Rb+and Cs+preferentially bind to carbonyl groups, whereas the multivalent Mn2+, Co2+and Yb3+interact with carboxylic groups. This work elucidates the basis of the effect of the Hofmeister cation series on protein solubility.


2012 ◽  
Vol 36 (1) ◽  
pp. 89-96
Author(s):  
Md Mahbubul Alam ◽  
Faisal Ahmed ◽  
Rockshana Begum ◽  
Mizanur Rahman ◽  
Iqbal Ahmed Siddiquey ◽  
...  

The cyclic (2+2) template condensation of pyridine-2,6-dicarboxaldehyde with 1,2-Bis(2- aminoethoxy) ethane using Pb(SCN)2 gave dinuclear lead (II) complex, Pb2L1(SCN)4 where L1 is a tetra-Schiff-base macrocycle. The transmetallation treatment of Pb2L1(SCN)4 with Cu(ClO4)2.6H2O yield the complex, [Cu2L1(SCN)3(ClO4)] which has been characterized by elemental analysis, IR, ESI-MS spectroscopy and X-ray crystallography. On the basis of spectral data, different geometry of Cu2+ has been suggested. DOI: http://dx.doi.org/10.3329/jbas.v36i1.10924 Journal of Bangladesh Academy of Sciences, Vol. 36, No. 1, 89-96, 2012


2013 ◽  
Vol 43 (2) ◽  
pp. 108-115 ◽  
Author(s):  
Deborah C. Bebout ◽  
Edith V. Bowers ◽  
Rachel E. Freer ◽  
Margaret E. Kastner ◽  
Damon A. Parrish ◽  
...  

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).


Author(s):  
Robert A. Grant ◽  
Laura L. Degn ◽  
Wah Chiu ◽  
John Robinson

Proteolytic digestion of the immunoglobulin IgG with papain cleaves the molecule into an antigen binding fragment, Fab, and a compliment binding fragment, Fc. Structures of intact immunoglobulin, Fab and Fc from various sources have been solved by X-ray crystallography. Rabbit Fc can be crystallized as thin platelets suitable for high resolution electron microscopy. The structure of rabbit Fc can be expected to be similar to the known structure of human Fc, making it an ideal specimen for comparing the X-ray and electron crystallographic techniques and for the application of the molecular replacement technique to electron crystallography. Thin protein crystals embedded in ice diffract to high resolution. A low resolution image of a frozen, hydrated crystal can be expected to have a better contrast than a glucose embedded crystal due to the larger density difference between protein and ice compared to protein and glucose. For these reasons we are using an ice embedding technique to prepare the rabbit Fc crystals for molecular structure analysis by electron microscopy.


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