The giant protein titin plays a critical role in regulating the passive elasticity of muscles, mainly through the stochastic unfolding and refolding of its numerous immunoglobulin domains in the I-band of sarcomeres. The unfolding dynamics of titin immunoglobulin domains at a force range greater than 100 pN has been studied by atomic force microscopy, while that at smaller physiological forces has not been measured before. By using magnetic tweezers, it is found that the titin I27 domain unfolds in a surprising non-monotonic force-dependent manner at forces smaller than 100 pN, with the slowest unfolding rate occurring around 22 pN. We further demonstrate that a model with single unfolding pathway taking into account the elasticity of the transition state can reproduce the experimental results. These results provide important novel insights into the regulation mechanism of the passive elasticity of muscle tissues.

The first efficient intermolecular addition of nitroalkanes to activated enynes for asymmetric synthesis of 2,3-allenoates is described. It is a new addition to the limited available strategies for catalytic asymmetric synthesis of allenoates. Enabled by a new bifunctional catalyst, a range of trisubstituted allenoates can be obtained in excellent chemical and optical purity. These allenoate products with a pendant 2-nitroethyl α-substituent are useful chiral building blocks.

The giant protein titin playsacritical role in regulating the passive elasticity of muscles,m ainly through the stochastic unfolding and refolding of its numerous immunoglobulin domains in the I-band of sarcomeres.T he unfolding dynamics of titin immunoglobulin domains at af orce range greater than 100 pN has been studied by atomic force microscopy, while that at smaller physiological forces has not been measured before.B yu sing magnetic tweezers,i ti s found that the titin I27 domain unfolds in as urprising nonmonotonic force-dependent manner at forces smaller than 100 pN,w ith the slowest unfolding rate occurring around 22 pN.W ef urther demonstrate that am odel with single unfolding pathway taking into account the elasticity of the transition state can reproduce the experimental results.T hese results provide important novel insights into the regulation mechanism of the passive elasticity of muscle tissues.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: http://dx.

The QSAL provides effective treatment for removal of labial lentigines associated with PJS.