A comparison of muscle thin filament models obtained from electron microscopy reconstructions and low-angle X-ray fibre diagrams from non-overlap muscle
A comparison of muscle thin filament models obtained from electron microscopy reconstructions and low-angle X-ray fibre diagrams from non-overlap muscle
复制标题
DOI：
10.1016/j.jsb.2006.02.020
复制
发表时间：
2006-08-01
影响因子：
3
通讯作者：
Holmes, Kenneth C.
中科院分区：
文献类型：
--
作者：
Poole, Katrina J. V.;Lorenz, Michael;Holmes, Kenneth C.
横纹肌收缩的调节涉及肌钙蛋白和原肌球蛋白与肌动蛋白细丝相互作用的改变。在静息肌肉中，肌动蛋白上的肌凝蛋白结合位点被盘绕蛋白原肌凝蛋白阻断。在肌肉活化过程中，Ca2+结合肌钙蛋白改变原肌凝蛋白在肌动蛋白上的位置，导致肌动蛋白-肌凝蛋白的循环相互作用，伴随肌肉收缩。肌钙蛋白-原肌球蛋白立体调节的证据来自x射线数据[Haselgrove， J.C, 1972]。脊椎动物横纹肌中含有肌动蛋白的细丝构象改变的x射线证据。冷泉港会议生物工程学报，36 (3):341-352；赫胥黎，1972。收缩过程中肌动蛋白和肌球蛋白纤维的结构变化。冷泉港会议生物工程学报，37 (3):361-376；Parry， D.A, Squire, j.m., 1973。原肌球蛋白在肌肉调节中的结构作用：松弛和收缩肌肉的x射线衍射图分析。j .年检。[J]张志强，张志强，张志强，等。电子显微镜（EM）数据分析[J] .中国生物医学工程学报，2004,18(2):444 - 444。骨骼肌收缩的调节。2。原肌球蛋白-肌钙蛋白复合物与肌动蛋白相互作用的结构研究。j .年检。《生物科学》第72期，619-632页，O'Brien， E.J, Gillis， J.M, Couch， J. 1975。重建肌肉细丝的准晶体对称性和分子排列。j .年检。生物医学工程学报，1999,41 -475；雷曼，W.，克雷格，R.，维伯特，P., 1994。三维重建显示Ca（2+）诱导的原肌球蛋白在鲎细丝中的运动。[自然，368,65-67]每一种都有其独特的优势和局限性。在这里，我们汇集了来自皮拉尼等人的单薄细丝的EM分析的一些最新信息[皮拉尼，A.，徐，C.，哈奇，V.，克雷格，R., Tobacman, l.s.，雷曼，W.(2005)]。放松和激活肌肉细丝的单粒子分析。j .年检。用同步加速器x射线数据从非重叠的肌肉纤维，以完善横纹肌细丝的模型。这是通过结合当前的肌动蛋白、原肌凝蛋白、肌钙蛋白和肌凝蛋白亚片段-1的原子分辨率结构来完成的。将这些原子坐标拟合到EM重建中，我们提出了完全符合空间调节机制的细丝的原子模型。此外，将原子模型与皮肤肌纤维的衍射数据进行拟合，拉伸到不重叠以防止交叉桥结合，产生了非常相似的结果，包括Ca2+诱导的原肌球蛋白方位角位置的大位移，但肌动蛋白结构的变化很小，肌钙蛋白位置的明显改变。(c) 2006爱思唯尔公司版权所有。
The regulation of striated muscle contraction involves changes in the interactions of troponin and tropomyosin with actin thin filaments. In resting muscle, myosin-binding sites on actin are thought to be blocked by the coiled-coil protein tropomyosin. During muscle activation, Ca2+ binding to troponin alters the tropomyosin position on actin, resulting in cyclic actin-myosin interactions that accompany muscle contraction. Evidence for this steric regulation by troponin-tropomyosin comes from X-ray data [Haselgrove, J.C., 1972. X-ray evidence for a conformational change in the actin-containing filaments of verterbrate striated muscle. Cold Spring Habor Symp. Quant. Biol. 37, 341-352; Huxley, H.E., 1972. Structural changes in actin and myosin-containing filaments during contraction. Cold Spring Habor Symp. Quant. Biol. 37, 361-376; Parry, D.A., Squire, J.M., 1973. Structural role of tropomyosin in muscle regulation: analysis of the X-ray diffraction patterns from relaxed and contracting muscles. J. Mot. Biol. 75, 33-55] and electron microscope (EM) data [Spudich, J.A., Huxley, H.E., Finch, J., 1972. Regulation of skeletal muscle contraction. II. Structural studies of the interaction of the tropomyosin-troponin complex with actin. J. Mot. Biol. 72, 619-632, O'Brien, E.J., Gillis, J.M., Couch, J., 1975. Symmetry and molecular arrangement in paracrystals of reconstituted muscle thin filaments. J. Mot. Biol. 99, 461-475; Lehman, W., Craig, R., Vibert, P., 1994. Ca(2+)-induced tropomyosin movement in Limulus thin filaments revealed by three-dimensional reconstruction. Nature 368, 65-67] each with its own particular strengths and limitations. Here we bring together some of the latest information from EM analysis of single thin filaments from Pirani et al. [Pirani, A., Xu, C., Hatch, V., Craig, R., Tobacman, L.S., Lehman, W. (2005). Single particle analysis of relaxed and activated muscle thin filaments. J. Mot. Biol. 346, 761-772], with synchrotron X-ray data from non-overlapped muscle fibres to refine the models of the striated muscle thin filament. This was done by incorporating current atomic-resolution structures of actin, tropomyosin, troponin and myosin subfragment-1. Fitting these atomic coordinates to EM reconstructions, we present atomic models of the thin filament that are entirely consistent with a steric regulatory mechanism. Further-more, fitting the atomic models against diffraction data from skinned muscle fibres, stretched to non-overlap to preclude crossbridge binding, produced very similar results, including a large Ca2+-induced shift in tropomyosin azimuthal location but little change in the actin structure or apparent alteration in troponin position. (c) 2006 Elsevier Inc. All rights reserved.