When placed in a crowded environment, a semiflexible tube is forced to fold so as to make a more compact shape. One compact shape that often arises in nature is the tight helix, especially when the tube thickness is of comparable size to the tube length. In this paper we use an excluded volume effect to model the effects of crowding. This gives us a measure of compactness for configurations of ...

Summary: Waggawagga is a web-based tool for the comparative visualization of coiled-coil predictions and the detection of stable single a-helices (SAH domains). Overview schemes show the predicted coiled-coil regions found in the query sequence and provide sliders, which can be used to select segments for detailed helical wheel and helical net views. A window-based score has been developed to p...

the thin gelatin films, prepared by casting of gelatin solutions at different drying temperatures, had different molecular morphologies as monitored, using wide angle x-ray diffraction (waxd) and differential scanning calorimetry (dsc) techniques. it was revealed that gelatin films dried at lower temperatures showed markedly higher crystalline or helical structure with slightly higher tg and lo...

We theoretically study the electrical conductivity in a one-dimensional helimagnet whose spin texture changes from helimagnetic to conical magnetic, and forced ferromagnetic state while increasing magnetic field along helical axis. find that at zero depends on electron filling coefficient of spin-charge coupling. also nonlinearly applied field, magnetoresistance becomes negative positive depend...

The natural frequency of cantilevered bistable carbon/epoxy reeled composite (BRC) slit tubes constructed from combinations of braided and unidirectional (UD) plies is optimized with respect to fiber orientation angles and laminate stacking sequences. BRC tubes have the same geometry as a carpenter’s tape; however, they also have a second stable configuration in the coiled state, and it is cons...

Retrovirus entry into cells follows receptor binding by the surface-exposed envelope glycoprotein (Env) subunit (SU), which triggers the membrane fusion activity of the transmembrane (TM) protein. TM protein fragments expressed in the absence of SU adopt helical hairpin structures comprising a central coiled coil, a region of chain reversal containing a disulfide-bonded loop, and a C-terminal s...

Crick envisaged the alpha-helical coiled coil to result from systematic bending of an alpha-helix such that every seventh residue was structurally equivalent, and he derived equations for the coordinates of the backbone atoms. Crick's predictions were vindicated experimentally and coiled-coil sequences were shown to have hydrophobic residues alternately spaced 3 and 4 residues apart. Nonetheles...

To improve our understanding of conformational transitions in proteins, we are attempting the de novo design of peptides that switch structural state. Here, we describe coiled-coil peptides with sequence and structural duality; that is, features compatible with two different coiled-coil motifs superimposed within the same sequence. Specifically, we promoted a parallel leucine-zipper dimer under...