Rief M, Gautel M, Oesterhelt F, Fernandez J M, Gaub H E
Lehrstuhl für Angewandte Physik, München, Germany.
Science. 1997 May 16;276(5315):1109-12. doi: 10.1126/science.276.5315.1109.
Single-molecule atomic force microscopy (AFM) was used to investigate the mechanical properties of titin, the giant sarcomeric protein of striated muscle. Individual titin molecules were repeatedly stretched, and the applied force was recorded as a function of the elongation. At large extensions, the restoring force exhibited a sawtoothlike pattern, with a periodicity that varied between 25 and 28 nanometers. Measurements of recombinant titin immunoglobulin segments of two different lengths exhibited the same pattern and allowed attribution of the discontinuities to the unfolding of individual immunoglobulin domains. The forces required to unfold individual domains ranged from 150 to 300 piconewtons and depended on the pulling speed. Upon relaxation, refolding of immunoglobulin domains was observed.
单分子原子力显微镜（AFM）被用于研究肌联蛋白的力学性质，肌联蛋白是横纹肌中巨大的肌节蛋白。单个肌联蛋白分子被反复拉伸，并记录所施加的力作为伸长的函数。在大伸长时，恢复力呈现出锯齿状模式，其周期在25至28纳米之间变化。对两种不同长度的重组肌联蛋白免疫球蛋白片段的测量显示出相同的模式，并允许将不连续性归因于单个免疫球蛋白结构域的展开。展开单个结构域所需的力范围为150至300皮牛顿，并取决于拉伸速度。在松弛时，观察到免疫球蛋白结构域的重新折叠。
