From pico to nano: biofunctionalization of cube-octameric silsesquioxanes by peptides and miniproteins

Polyhedral silsesquioxanes are considered valuable conjugation scaffolds. Nevertheless, only a few examples of silsesquioxane-assembled peptide oligomers have been reported to date. We developed a new bioorthogonal cube-octameric silsesquioxane (COSS) scaffold bearing eight aminooxy coupling sites allowing for the conjugation of diverse peptides via oxime ligation. We found that the coupling efficacy depends on the ligand in view of steric hindrance and electrostatic repulsion. For the first time scaffold-based conjugation of cystine-knot miniproteins having a backbone of about thirty amino acids was successfully accomplished without loss of bioactivity. Atomic force microscopy (AFM) provided further knowledge on the size of COSS verifying them as picoscaffolds growing upon bioconjugation to nano-dimension.     

Metamictization in zircon: Raman investigation following a Rietveld approach. Part II: Sampling depth implication and experimental data

Profile line deconvolution following a Rietveld approach is applied to Raman spectra obtained from natural zircon grains from the European Alps. The corrected bandwidths are in perfect agreement with the values obtained from an established correction method (after Irmer) as far as the area of validity of the latter is concerned. For Raman active modes smaller than that, the Rietveld approach also yields accurate values for the true Raman bandwidth. Moreover, changes to instrument parameters are compensated by the correction routine. As for the studied zircon grains, Raman spectroscopy was shown to be a suitable tool for the examination of zoning (i.e. regions which show a variable degree of radiation‐induced damage because of a different amount of incorporated uranium and/or thorium). This is complicated by the fact that the measured Raman signal is not restricted to the depth expected from the axial resolution (several micrometers) but a significant contribution comes from a comparatively large excitation volume (tens of micrometer deep). This sampling volume, however, lies within the same order of magnitude as zoning, which itself is blurred by the range of amorphization‐causing alpha‐particles. Copyright © 2008 John Wiley & Sons, Ltd.     

Study of structural and electronic transport properties of Ce-doped LaMnO3

The structural and electronic transport properties of La_1−x Ce _x MnO₃ (x=0.0–1.0) have been studied. All the samples exhibit orthorhombic crystal symmetry and the unit cell volume decreases with Ce doping. They also make a metal-insulator transition (MIT) and transition temperature increases with increase in Ce concentration up to 50% doping. The system La_0.5Ce_0.5MnO₃ also exhibits MIT instead of charge-ordered state as observed in the hole doped systems of the same composition.     

Between two worlds: a comparative study on in vitro and in silico inhibition of trypsin and matriptase by redox-stable SFTI-1 variants at near physiological pH

A comparative study on in vitro and in silico inhibition of trypsin and matriptase by derivatives of the sunflower trypsin inhibitor-1 at near physiological pH is reported. Besides wild-type bicyclic SFTI-1, monocyclic variants possessing native cystine as well as redox-stable triazolyl side-chain macrocyclization motifs were studied for the first time in matriptase inhibition assays. Interestingly, monocyclic SFTI-1[1,14] demonstrated higher potency against this pharmacologically relevant protease compared to its bicyclic counterpart. Structural analysis of binding/inhibition of investigated SFTI-1 derivatives was performed using a combination of molecular dynamics simulations and docking experiments. In silico data were in good accordance with in vitro results, indicating the importance of the terminal inhibitor regions for the affinity towards matriptase. Presented work gives new perspectives for the optimization of the SFTI-1 framework towards in vivo applications.     

Two connected inverse spectral transforms

We establish a transformation which connects the potentials of the one-dimensional Dirac and Klein-Gordon operators. This transformation links the solutions of the nonlinear evolution equations solvable by means of the two inverse spectral transforms which use the Dirac and Klein-Gordon direct and inverse spectral problems.