7 research outputs found

    Two-Molecule Force Spectroscopy on Proteins

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    Many elastomeric proteins, which play important roles in a wide range of biological processes, exist as parallel/antiparallelly arranged dimers or multimers to perform their mechanobiological functions. For example, in striated muscle sarcomeres, the giant muscle protein titin exists as hexameric bundles to mediate the passive elasticity of muscles. However, it has not been possible to directly probe the mechanical properties of such parallelly arranged elastomeric proteins. And it remains unknown if the knowledge obtained from single-molecule force spectroscopy studies can be directly extrapolated to such parallelly/antiparallelly arranged systems. Here, we report the development of atomic force microscopy (AFM)-based two-molecule force spectroscopy to directly probe the mechanical properties of two elastomeric proteins that are arranged in parallel. We developed a twin-molecule approach to allow two parallelly arranged elastomeric proteins to be picked up and stretched simultaneously in an AFM experiment. Our results clearly revealed the mechanical features of such parallelly arranged elastomeric proteins during force–extension measurements and allowed for the determination of mechanical unfolding forces of proteins in such an experimental setting. Our study provides a general and robust experimental strategy to closely mimic the physiological condition of such parallel elastomeric protein multimers

    Bis(boryl anion)-Substituted Pyrenes: Syntheses, Characterizations, and Crystal Structures

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    The two new diboranes <b>1</b> and <b>2</b> connected by a pyrene moiety at the 1,6- and 1,3-positions, respectively, were synthesized, and their two-electron-reduction reactions were investigated. The doubly reduced species <b>1</b><sup>••2–</sup> is silent in electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopic measurements, suggesting a quasi-quinoidal structure with a diradical character of <b>1</b><sup>••2–</sup>, which has a singlet–triplet gap of 6.6 kcal mol<sup>–1</sup> as determined by theoretical calculations. In contrast, the reduction product <b>2</b><sup>••2–</sup> is EPR active and theoretical calculations indicate that <b>2</b><sup>••2–</sup> has an open-shell singlet ground state with a singlet–triplet energy gap of 4.9 kcal mol<sup>–1</sup>

    JTXK granule decreased the plasma insulin concentration, and improved insulin sensitivity in T2DM KKAy mice.

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    <p>(A) Serum insulin concentration was reduced by JTXK granule at the end of the treatment. (B) Serum fasting glucose levels of the mice in each group. (C) HOMA-IR of the mice in each group. (D) ISI of the mice in each group. Data are expressed as the mean ± SE. *P<0.05, **P<0.01 vs. control group (T2DM KKAy mice). ## P<0.01 vs. non-diabetic control group (C57BL/6J mice). HOMA-IR = FBG (mmol/l)×FINS (μU/ml)/22.5; ISI = 1/[FBG (mmol/l)×FINS (μU/ml)].</p

    JTXK granule altered mRNA expression in the PI3K/Akt signalling pathway in skeletal muscle.

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    <p>IRS-1, insulin receptor substrate-1; PI3K, phosphatidylinositol 3-kinase; Akt, serine/threonine-protein kinase; p-Akt, phosphorylated Akt; Glut4, glucose transporter 4; GSK3β, Glycogen synthase kinase 3 β. Data are expressed as the mean ± SE of six mice in each group. *P<0.05, **P<0.01 vs. control group (T2DM KKAy mice).</p

    JTXK granule improved results of oral glucose tolerance test (OGTT) in T2DM KKAy mice.

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    <p>A and C showed results of OGTT in each group at the fifth and the tenth week. B and D showed area under the curve (AUC) of the OGTT among groups at the fifth and the tenth weeks. Data are expressed as the mean ± SE of ten mice in each group. *P<0.05, **P<0.01 vs. control group (T2DM KKAy mice). ## P<0.01 vs. non-diabetic control group (C57BL/6J mice).</p

    JTXK granule decreased the plasma insulin concentration, and improved insulin sensitivity in T2DM KKAy mice.

    No full text
    <p>(A) Serum insulin concentration was reduced by JTXK granule at the end of the treatment. (B) Serum fasting glucose levels of the mice in each group. (C) HOMA-IR of the mice in each group. (D) ISI of the mice in each group. Data are expressed as the mean ± SE. *P<0.05, **P<0.01 vs. control group (T2DM KKAy mice). ## P<0.01 vs. non-diabetic control group (C57BL/6J mice). HOMA-IR = FBG (mmol/l)×FINS (μU/ml)/22.5; ISI = 1/[FBG (mmol/l)×FINS (μU/ml)].</p

    JTXK granule influenced relevant protein expression in the PI3K/Akt signalling pathway in skeletal muscle.

    No full text
    <p>IRS-1, insulin receptor substrate-1; PI3K, phosphatidylinositol 3-kinase; Akt, serine/threonine-protein kinase; p-Akt, phosphorylated Akt; Glut4, glucose transporter 4; GSK3β, Glycogen synthase kinase 3β. Data are expressed as the mean ± SE of six mice in each group. *P<0.05, **P<0.01 vs. control group (T2DM KKAy mice). ## P<0.01 vs. non-diabetic control group (C57BL/6J mice).</p
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