Physical Gelation of α-Helical Copolypeptides.

Owing to its rod-like α-helical secondary structure, the synthetic polypeptide poly(γ-benzyl-l-glutamate) (PBlG) can form physical and thermoreversible gels in helicogenic solvents such as toluene. The versatility of PBlG can be increased by introducing functionalizable comonomers, such as allylglycine (AG). In this work we examined the secondary structure of PBlG and a series of statistical poly(γ-benzyl-l-glutamate-co-allylglycine) copolypeptides, varying in composition and chain length, by circular dichroism (CD), Fourier-transform infrared (FTIR) and Raman spectroscopy, and wide-angle X-ray scattering (WAXS).

Construction of three-dimensional DNA hydrogels from linear building blocks.

A three-dimensional DNA hydrogel was generated by self-assembly of short linear double-stranded DNA (dsDNA) building blocks equipped with sticky ends. The resulting DNA hydrogel is thermoresponsive and the length of the supramolecular dsDNA structures varies with temperature. The average diffusion coefficients of the supramolecular dsDNA structures formed by self-assembly were determined by diffusion-ordered NMR spectroscopy (DOSY NMR) for temperatures higher than 60 °C.

Mutations in desmin's carboxy-terminal "tail" domain severely modify filament and network mechanics.

Inherited mutations in the gene coding for the intermediate filament protein desmin have been demonstrated to cause severe skeletal and cardiac myopathies. Unexpectedly, some of the mutated desmins, in particular those carrying single amino acid alterations in the non-alpha-helical carboxy-terminal domain ("tail"), have been demonstrated to form apparently normal filaments both in vitro and in transfected cells. Thus, it is not clear if filament properties are affected by these mutations at all.

Desmin and vimentin intermediate filament networks: their viscoelastic properties investigated by mechanical rheometry.

We have investigated the viscoelastic properties of the cytoplasmic intermediate filament (IF) proteins desmin and vimentin. Mechanical measurements were supported by time-dependent electron microscopy studies of the assembly process under similar conditions. Network formation starts within 2 min, but it takes more than 30 min until equilibrium mechanical network strength is reached.