Detection of the transition between the two myosin isoforms α- and β-myosin in living cardiomyocytes is essential for understanding cardiac physiology and pathology. In this study, the differences in symmetry of polarization spectra obtained from α- and β-myosin in various mammalian ventricles and propylthiouracil-treated rats are explored through polarization-dependent second harmonic generation microscopy. Here, we report for the, to our knowledge, first time that α- and β-myosin, as protein crystals, possess different symmetries: the former has C6 symmetry, and the latter has C3v. A single-sarcomere line scan further demonstrated that the differences in polarization-spectrum symmetry between α- and β-myosin came from their head regions: the head and neck domains of α- and β-myosin account for the differences in symmetry. In addition, the dynamic transition of the polarization spectrum from C6 to C3v line profile was observed in a cell culture in which norepinephrine induced an α- to β-myosin transition.

中文翻译：

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偏振相关SHG显微镜研究心肌肌球蛋白表达转变

检测活心肌细胞中两种肌球蛋白同工型 α- 和 β-肌球蛋白之间的转变对于理解心脏生理学和病理学至关重要。在这项研究中，通过偏振相关的二次谐波发生显微镜探索了在各种哺乳动物心室和丙硫氧嘧啶治疗的大鼠中从 α- 和 β-肌球蛋白获得的偏振光谱对称性的差异。在这里，据我们所知，我们首次报道了作为蛋白质晶体的 α- 和 β-肌球蛋白具有不同的对称性：前者具有 C6 对称性，后者具有 C3v。单肌节线扫描进一步证明 α- 和 β- 肌球蛋白之间偏振光谱对称性的差异来自它们的头部区域：α- 和 β- 肌球蛋白的头颈部域解释了对称性的差异。此外，