TITINS - GIANT PROTEINS IN CHARGE OF MUSCLE ULTRASTRUCTURE AND ELASTICITY
TITINS - GIANT PROTEINS IN CHARGE OF MUSCLE ULTRASTRUCTURE AND ELASTICITY
复制标题
DOI：
10.1126/science.270.5234.293
复制
发表时间：
1995-10-13
期刊：
影响因子：
56.9
通讯作者：
KOLMERER, B
中科院分区：
文献类型：
--
作者：
LABEIT, S;KOLMERER, B
脊椎动物的横纹肌除了有粗的和细的肌丝外，还含有由巨大的肌联蛋白形成的第三种肌丝系统。单个肌联蛋白分子从Z盘延伸到M线，并且长于1微米。肌联蛋白丝有助于肌肉组装和静息张力，但由于蛋白质的大尺寸，更多细节尚不清楚。测定了人心肌肌联蛋白的DNA全序列。82-腺苷酸酶互补DNA预测了由244个拷贝的免疫球蛋白和纤连蛋白III型（FN 3）结构域组成的3兆道尔顿蛋白。肌联蛋白A带区序列的结构表明了为什么粗丝结构在脊椎动物中是保守的。在I带区域，不同的被动张力的肌肉肌联蛋白序列的比较确定了两个元素，与组织硬度。这表明肌联蛋白可能充当串联的两个弹簧。弹簧的差异表达为脊椎动物横纹肌肌节长度和静息张力的多样性提供了分子解释。
In addition to thick and thin filaments, vertebrate striated muscle contains a third filament system formed by the giant protein titin. Single titin molecules extend from Z discs to M lines and are longer than 1 micrometer. The titin filament contributes to muscle assembly and resting tension, but more details are not known because of the large size of the protein. The complete complementary DNA sequence of human cardiac titin was determined. The 82-kilobase complementary DNA predicts a 3-megadalton protein composed of 244 copies of immunoglobulin and fibronectin type III (FN3) domains. The architecture of sequences in the A band region of titin suggests why thick filament structure is conserved among vertebrates. In the I band region, comparison of titin sequences from muscles of different passive tension identifies two elements that correlate with tissue stiffness. This suggests that titin may act as two springs in series. The differential expression of the springs provides a molecular explanation for the diversity of sarcomere length and resting tension in vertebrate striated muscles.