Guanosine-rich DNA sequences have the potential to adopt four-stranded conformations termed quadruplexes. The chromosomes of higher organisms are capped by so-called telomeres that are composed of repeats of the sequence TTAGGG. Up to 200 nucleotides of the G-rich strand form an overhang that is suspected to fold into intramolecular G-quadruplexes. Since induction of quadruplexes at the telomer...

We have determined the atomic structure of the bacteriochlorophyll c (BChl c) assembly in a huge light-harvesting organelle, the chlorosome of green photosynthetic bacteria, by solid-state NMR. Previous electron microscopic and spectroscopic studies indicated that chlorosomes have a cylindrical architecture with a diameter of approximately 10 nm consisting of layered BChl molecules. Assembly st...

The design principles of spider dragline silk, nature's high-performance fiber, are still largely unknown, in particular for the noncrystalline glycine-rich domains, which form the bulk of the material. Here we apply two-dimensional solid-state NMR to determine the distribution of the backbone torsion angles (phi,psi) as well as the orientation of the polypeptide backbone toward the fiber at bo...

Helium displacement and nitrogen adsorption techniques were used to determine the density and porosity, respectively, of freeze-dried cell walls isolated from Bacillus megaterium KM and Saccharomyces cerevisiae. The densities were 1.302 and 1.180 g/cm3, respectively, suggesting noncrystalline solids. The porosities were extremely small, indicating that the cell walls had collapsed and become es...

We give a strong evidence that noncrystalline materials such as quasicrystals or incommensurate solids are not exceptions but rather are generic in some regions of a phase space. We show this by constructing classical lattice gas models with translationinvariant, finite-range interactions and with a unique quasiperiodic ground state which is stable against small perturbations of two-body potent...

The analysis of double-crystal x-ray rocking curves of single-crystal layered structures can give valuable information on layer strains, displacement of atoms from normal lattice sites (which reduces the structure factor), crystallographic misorientations, and crystal defects. Both strains and misorientations cause shifts in the Bragg angle. These two effects are readily separated using two or ...

The crystalline sponge method is a technique that provides the ability to elucidate absolute structure of noncrystalline or hard crystallize compounds through single-crystal X-ray diffraction by removing need obtain crystals target compound. In this study sponges {[(ZnX2)3(2,4,6-tris(4-pyridyl)-1,3,5-trazine)2].x(solvent)}n (X = I, Br) were used structures agrochemical active ingredients metala...