We have studied the oligomerization of an alpha-helical coiled-coil using as an example a peptide corresponding to the C-terminal domain of cartilage matrix protein. By replacing one arginine residue, which forms an interchain ionic interaction with a glutamic acid residue, with glutamine, we found that this peptide assembles into a homotetramer at neutral pH in contrast to the native molecule ...

The transient process accompanied by extreme acceleration in the conical sections of hydraulic systems (e.g., draft tube, diffuser) can induce large cavitation bubbles both at closed ends and bulk liquid. collapses cause severe damage to solid walls. We conduct experiments tubes with different conical-frustum shaped `tube-arrest' method observe generated these two locations. For close end we pr...

A susceptibility gene for psoriasis, a chronic skin disorder, resides in chromosome 6p near the HLA-C locus. Sequencing of the region has allowed the identification of a new gene, HCR. We found that HCR is highly polymorphic with at least 12 coding variants. An association study of the new HCR polymorphisms and the previously suggested susceptibility alleles HLA-Cw*0602 and corneodesmosin allel...

The crystal structure at 2.0-A resolution of an 81-residue N-terminal fragment of muscle alpha-tropomyosin reveals a parallel two-stranded alpha-helical coiled-coil structure with a remarkable core. The high alanine content of the molecule is clustered into short regions where the local 2-fold symmetry is broken by a small (approximately 1.2-A) axial staggering of the helices. The joining of th...

Bacterial flagella assume different helical shapes during the tumbling phase of a bacterium but also in response to varying environmental conditions. Force-extension measurements by Darnton and Berg explicitly demonstrate a transformation from the coiled to the normal helical state (N.C. Darnton, H.C. Berg, Biophys. J. 92, 2230 (2007)). We here develop an elastic model for the flagellum based o...

A theory of the helix-coil transition for in-register, two-chain, a-helical, coiled coils such as tropomyosin and paramyosin is developed. The treatment differs from those formulated previously for DNAor collagen-like double helices; in the present treatment, isolated single chains and each of the two strands in the dimer may be partially helical. We calculate the fraction of helix in the two-c...

Spectrin repeats fold into triple helical coiled-coils comprising approximately 106 amino acid residues. Using an AFM-related technique we measured the force required to mechanically unfold these repeats to be 25 to 35 pN. Under tension, individual spectrin repeats unfold independently and in an all-or-none process. The dependence of the unfolding forces on the pulling speed reveals that the co...

Coiled coils are a major motif in proteins and orchestrate multimerization of various complexes important for biological processes. Inhibition of coiled coil-mediated interactions has significant biomedical potential. However, general approaches that afford short peptides with defined coiled coil conformation remain elusive. We evaluated several strategies to stabilize minimal helical bundles, ...