Solution structure and dynamics of mouse ARMET

AbstractARMET is an endoplasmic reticulum (ER) stress-inducible protein that is required for maintaining cell viability under ER stress conditions. However, the exact molecular mechanisms by which ARMET protects cells are unknown. Here, we have analyzed the solution structure of ARMET. ARMET has an entirely α-helical structure, which is composed of two distinct domains. Positive charges are dispersed on the surfaces of both domains and across a linker structure. Trypsin digestion and 15N relaxation experiments indicate that the tumbling of the N-terminal and C-terminal domains is effectively independent. These results suggest that ARMET may hold a negatively charged molecule using the two positively charged domains

Crystallization of polypropylene near the surface in injection-molded plaques: A comparison of morphology and a numerical analysis

Skin morphology formation on injection-molded isotactic polypropylene (PP) was investigated using micro-beam synchrotron wide-angle X-ray diffraction and numerical simulation. The 1-20 Î?m depth range was characterized with an X-ray beam of 0.273 Î?m Ï? 0.389 Î?m in size. From an evaluation of doping nucleating agents (NA) in PP, the NAs did not work at a depth of 1 Î?m. α-specified NA affected crystallization within a 5-Î?m depth. β-specified PP showed α-form crystallinity at the 5-20 Î?m depth. The mesomorphic crystal near the surface showed extremely high orientation. From viscoelastic flow simulation, PP molecules near the surface were oriented in the flow direction by extensional flow in the flow front, but freezing occurred faster than flow-induced crystallization. It was estimated that the delay of crystallization occurred during the transient temperature. The deformation rate did not cause a difference in crystal morphology near the surface, but the cooling rate did. Copyright © 2009 Society of Plastics Engineers

De Novo Design of Foldable Proteins with Smooth Folding Funnel Automated Negative Design and Experimental Verification

AbstractDe novo sequence design of foldable proteins provides a way of investigating principles of protein architecture. We performed fully automated sequence design for a target structure having a three-helix bundle topology and synthesized the designed sequences. Our design principle is different from the conventional approach, in that instead of optimizing interactions within the target structure, we design the global shape of the protein folding funnel. This includes automated implementation of negative design by explicitly requiring higher free energy of the denatured state. The designed sequences do not have significant similarity to those of any natural proteins. The NMR and CD spectroscopic data indicated that one designed sequence has a well-defined three-dimensional structure as well as α-helical content consistent with the target

Terahertz Time-Domain Spectroscopy of Amino Acids and Polypeptides

Frequency-dependent absorption coefficients and refractive indices of amino acids (glycine and l-alanine) and polypeptides (polyglycine and poly-l-alanine) in the wavenumber region from 7 to 55 cm(−1) were measured by terahertz time-domain spectroscopy. A vibrational band was observed at 45.5 cm(−1) for polyglycine, which was assigned as an interchain mode. The reduced absorption cross sections of the amino acids and polypeptides show power-law behavior. The exponents are different between the monomers and polymers, and those of the two polypeptides suggest that the time dependences of the total dipole moments are similar in the timescale of subpico- to picoseconds