抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Crystalline metal-organic frameworks (MOFs) are formed by reticular synthesis, which creates strong bonds between inorganic and organic units. Careful selection of MOF constituents can yield crystals of ultrahigh porosity and high thermal and chemical stability. These characteristics allow the interior of MOFs to be chemically altered for use in gas separation, gas storage, and catalysis, among other applications. The precision commonly exercised in their chemical modification and the ability to expand their metrics without changing the underlying topology have not been achieved with other solids. MOFs whose chemical composition and shape of building units can be multiply varied within a particular structure already exist and may lead to materials that offer a synergistic combination of properties.

The Chemistry and Applications of Metal-Organic Frameworks

J. Appl. Cryst.の発刊に際して

The widespread use of controlled molecular-level motion in key natural processes suggests that great rewards could come from bridging the gap between the present generation of synthetic molecular systems, which by and large rely upon electronic and chemical effects to carry out their functions, and the machines of the macroscopic world, which utilize the synchronized movements of smaller parts to perform specific tasks. This is a scientific area of great contemporary interest and extraordinary recent growth, yet the notion of molecular-level machines dates back to a time when the ideas surrounding the statistical nature of matter and the laws of thermodynamics were first being formulated. Here we outline the exciting successes in taming molecular-level movement thus far, the underlying principles that all experimental designs must follow, and the early progress made towards utilizing synthetic molecular structures to perform tasks using mechanical motion. We also highlight some of the issues and challenges that still need to be overcome.

Synthetic molecular motors and mechanical machines.

Based on fundamental chemistry, biotechnology and materials science have developed over the past three decades into today's powerful disciplines which allow the engineering of advanced technical devices and the industrial production of active substances for pharmaceutical and biomedical applications. This review is focused on current approaches emerging at the intersection of materials research, nanosciences, and molecular biotechnology. This novel and highly interdisciplinary field of chemistry is closely associated with both the physical and chemical properties of organic and inorganic nanoparticles, as well as to the various aspects of molecular cloning, recombinant DNA and protein technology, and immunology. Evolutionary optimized biomolecules such as nucleic acids, proteins, and supramolecular complexes of these components, are utilized in the production of nanostructured and mesoscopic architectures from organic and inorganic materials. The highly developed instruments and techniques of today's materials research are used for basic and applied studies of fundamental biological processes.

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Nanoparticles, Proteins, and Nucleic Acids: Biotechnology Meets Materials Science

Image plates have advantages over photographic films, which include wider dynamic range, higher detector quantum efficiency, reduced exposure time and large size. In this study, an on-line image-plate system has been used to record crystallographic data from a small crystal. In particular, synchrotron Laue data were recorded with lambda(min) = 0.455, lambda(max) = 1.180 A, in 20 images 10 degrees apart and with an exposure time of 0.3 s each from a crystal (0.02 x 0.05 x 0.25 mm) of a nickel-containing aluminophosphate, NiAPO. The Laue data were analyzed with the Daresbury Laue software, including the application of an absorption correction. The structure was solved by a combination of the Patterson method and successive difference Fourier calculations using SHELXS86 and SHELXL93; the final R value for 1934 unique reflections (all data) and 310 parameters was 7.90%. The structure agrees with that determined by monochromatic diffractometry using the same crystal and reported by Helliwell, Gallois, Kariuki, Kaucic & Helliwell [Acta Cryst. (1993), B49, 420-428] with an r.m.s. deviation of 0.03 A. Hence, this study shows the image-plate device to be very effective for synchrotron data collection and subsequent structure analysis from small crystals, i.e. 0.02 x 0.05 x 0.25 mm, in chemical crystallography as well as providing further confirmation of the practicability of Laue data in structure solution and refinement.

Image-plate synchrotron laue data collection and subsequent structural analysis of a small test crystal of a nickel-containing aluminophosphate.

The title compound, C20H19NO2S2, is formed by a palladium–copper-catalyzed reaction between 4-methyl-N-[2-(prop-2-ynyl­sul­fanyl)­phenyl]­benzene­sul­fon­amide and p-iodo­toluene. The mol­ecules contain three essentially planar parts, namely an amino­thio­phenol moiety (A), a toluene­sulfone moiety excluding the oxo ligands (B) and a tolyl group (C), approximately orthogonal to each other; the dihedral angles A/B, A/C and B/C are 111.6 (1), 89.3 (1) and 101.4 (1)°, respectively. Intermolecular N—H⋯O hydrogen bonds link the mol­ecules into infinite one-dimensional chains.

4-Methyl-N-[2-(p-tolylsulfanyl)phenyl]benzene­sulfonamide

Poly(l2-chlorido-nonamethyl-l3-nitrato- tritin(IV)). Corrigendum

The title compound, C18H16O5, is a biologically active isocoumarin. The mol­ecule is almost planar. No hydrogen bonding is found in the crystal structure.

3-(3,4,5-trimethoxyphenyl)-1H-isochromen-1-one

The X-ray crystallography technique has greatly expanded in scope with the development and use of instrumentation at synchrotron sources, particularly in ‘large molecule’ protein crystallography and now also in ‘small molecule’ chemical crystallography. A variety of technical themes are described to illustrate this. Structure–function relationships are then discussed, firstly, in thermotropic liquid crystals, with respect to two octahexylphthalo-cyanines, and secondly, in the molecular recognition of the receptor binding site of the protein concanavalin A for its cognate sugar ligands.

Madeleine Helliwell

Papers

Image-plate synchrotron laue data collection and subsequent structural analysis of a small test crystal of a nickel-containing aluminophosphate.

4-Methyl-N-[2-(p-tolylsulfanyl)phenyl]benzenesulfonamide

Poly(l2-chlorido-nonamethyl-l3-nitrato- tritin(IV)). Corrigendum

3-(3,4,5-trimethoxyphenyl)-1H-isochromen-1-one

X-Ray Crystallography in Structural Chemistry and Molecular Biology

Madeleine Helliwell

Papers

Image-plate synchrotron laue data collection and subsequent structural analysis of a small test crystal of a nickel-containing aluminophosphate.

4-Methyl-N-[2-(p-tolylsulfanyl)phenyl]benzene­sulfonamide

Poly(l2-chlorido-nonamethyl-l3-nitrato- tritin(IV)). Corrigendum

3-(3,4,5-trimethoxyphenyl)-1H-isochromen-1-one

X-Ray Crystallography in Structural Chemistry and Molecular Biology

4-Methyl-N-[2-(p-tolylsulfanyl)phenyl]benzenesulfonamide