http://journals.iucr.org Acta Cryst. (2011). E67, o1112–o1113 (doi.org/10.1107/S1600536811012888)


4,4’-Bis[2-(3,5-dimethoxyphenyl)ethenyl]biphenyl a. coLLaS, M. ZeLLer and F. BLockhuyS Considering the success of recently marketed consumer technology


based on organic semiconductors, such as the OLED TV, it is clear that these materials have considerable potential for application in the opto- electronic devices of the future. Designing, synthesizing and character- izing new functional materials with properties tuned to match these applications remain central issues in the development of this technol- ogy. Detailed knowledge of their crystal structures is indispensible, in particular in the case of asymmetric systems which crystallize in polar space groups and display nonlinear optical activity.


Acta Cryst. (2011). F67, 424–428 (doi.org/10.1107/S1744309110052607)


Crystal structure of small protein crambin at 0.48 Å resolution a. SchMidt, M. teeter, e. Weckert and v.S. LaMZin Scientists at EMBL and DESY, Germany, and Boston College, USA,


obtained the highest resolution X-ray crystallographic structure of a bio- logical molecule, crambin, almost doubling the available data on this protein. Te researchers hope that the availability of this data will drive software development beyond its current limits so that details of pro- tein electronic structure could become attainable. Tis high-resolution structure was the first measured at the PETRA ring at DESY, where dedicated beamlines for biological samples are coming into operation.


J. Appl. Cryst. (2011). 44, 545–557 (doi.org/10.1107/S0021889811011691)


Scattering functions of Platonic solids X. Li, c.-y. SheW, L. he, F. MeiLLeur, d.a.a. MyLeS, e. Liu, y. ZhanG, G.S. SMith, k.W. herWiG, r. Pynn and W.-r. chen


Platonic solids, including tetrahedra, hexahedra, octahedra, dodeca-


heda and icosahedra, form an essential basis for the topology of con- densed matter in a variety of contexts. For each given geometry, the Debye spatial autocorrelation function g(r), the pair distance distribu- tion function p(r) and the intraparticle structure factor (form factor) S(Q) are calculated analytically and compared with the corresponding scattering functions of a spherical reference system with the same par- ticle volume. As an illustrative example, the quantitative interpretation


of small-angle scattering data from an icosahedral virus is presented. J. Synchrotron Rad. (2011). 18, 346–357 (doi.org/10.1107/S0909049511007163)


iUCr JoUrnals


Molecular (green) and unit-cell (brown) dipoles of an asymmetric organic semi- conductor.


Electron density (cyan) around Arg10 calculated at 0.65 Å before refinement with MoPro commenced. The Fo


toured at 2.7s (0.25 e Å-3 ) above the mean. –Fc Bonding electron density is indicated.


map is con-


The small-angle scattering form factors S(Q) of dodecahedron (left), icosahedron (right) and the isovolumetric hard sphere.


Effective scavenging at cryotemperatures: further increasing the dose tolerance of protein crystals e. de La Mora, i. carMichaeL and e.F. GarMan


Certain radical scavengers can reduce the rate of X-ray induced


radiation damage to macromolecular crystals during both room temperature and cryotemperature (100 K) data collection. In HEWL crystals held at 100 K, sodium nitrate, an electron scaven- ger, was found to double the dose (Gy = J kg-1


) tolerance as judged


from the rate of total diffraction intensity loss, and increase it by over 5 times when considering structural damage to the disulfide bonds. Te sequential electron density maps show the radiation


chemistry mechanism at work. IUCr Newsletter ♦ Volume 19, Number 2 ♦ 2011


Electron density maps of the Cys6–Cys127 bond in lysozyme after doses of 2.3 MGy, 12.3 MGy and 22.3 MGy, showing a nearby bound ordered nitrate ion being reduced to NO2


and then NO by


X-ray induced electrons, and thus affording pro- tection to the neighbouring disulfide bond.


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