Tubulin, an essential cytoskeletal protein, assembles into various morphologies by interacting with array of cellular factors. One these factors is the endogenous polyamine spermine, which may promote and stabilize tubulin assemblies. Nevertheless, assembled structures their formation pathways are poorly known. Here we show that spermine induced in vitro assembly several hierarchical architectu...

Polar residues lying between adjacent α-helical chains of coiled-coils often contribute to coiled-coil curvature and flexibility, while more typical core hydrophobic residues anneal the chains together. In tropomyosins, ranging from smooth and skeletal muscle to cytoplasmic isoforms, a highly conserved Asp at residue 137 places negative charges within the tropomyosin coiled-coil core in a posit...

The loops-excluded model of the a-helix to random coil transition of a-helical, two-chain, coiled coils (dimers) in which loop entropy acts to produce a single interacting helical stretch in the dimer has been reformulated in terms of the supermatrix method of Jernigan and Flory. It is demonstrated that the loops-excluded model is a member of the class of nearest-neighbor models. Serial matrix ...

Protein α-helical coiled coil structures are known to induce antibodies able to block critical functions in different pathogens. In a previous study, a total of 50 proteins of Plasmodium vivax erythrocytic asexual stages containing α-helical coiled coil structural motifs were identified in silico, and the corresponding peptides were chemically synthesized. A total of 43 peptides were recognized...

Troponin T (TnT), a thin filament myofibrillar protein, is essential for the Ca2+ regulation of striated muscle contraction in vertebrates, both in vivo and in vitro. To understand the role of TnT in this process, its interaction with two other troponin components, troponin I (TnI) and troponin C (TnC) was examined by using the yeast two hybrid system, which is a genetic approach to detect prot...

Helically coiled filaments are a frequent motif in nature. In situations commonly encountered in experiments coiled helices are squeezed flat onto two dimensional surfaces. Under such 2-D confinement helices form ”squeelices” peculiar squeezed conformations often resembling looped waves, spirals or circles. Using theory and Monte-Carlo simulations we illuminate here the mechanics and the unusua...

Previous studies have shown that the non-a-helical, amino-terminal head region of vimentin is essential for the formation and stability of vimentin intermediate filaments (TFs). In order to specify its target site on companion protein subunits, it was cut off from vimentin at amino acid position 96 with lysine-specific endoproteinase and allowed to react with intact vimentin and other IF protei...

It has been well established that heat transfer in a helical coil is higher than that in a corresponding straight pipe. However, the detailed characteristics of fluid flow and heat transfer inside helical coil is not available from the present literature. This paper brings out clearly the variation of local Nusselt number along the length and circumference at the wall of a helical pipe. Movemen...

Recently researchers have developed soft actuators capable of morphing into complex shapes taking inspiration from nature. In this paper, we a splay-nematic liquid crystal polymer network tapered actuator that can morph flat film to cone, mimicking the blooming single petal Calla Lily flower. We demonstrated formation conical tubes through finite element simulations and experiments. The influen...

Limited information is available on inherent stabilities of four-chain-coils. We have developed a model system to study this folding motif using synthetic peptides derived from sequences contained in the tetramerization domain of Lac repressor. These peptides are tetrameric as judged by both gel filtration and sedimentation equilibrium and the tetramers are fully helical as determined by CD. Th...