Single molecule force spectroscopy on polysaccharides by atomic force microscopy
Single molecule force spectroscopy on polysaccharides by atomic force microscopy
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DOI：
10.1126/science.275.5304.1295
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发表时间：
1997-02-28
期刊：
影响因子：
56.9
通讯作者：
Gaub, HE
中科院分区：
文献类型：
--
作者：
Rief, M;Oesterhelt, F;Gaub, HE
皮牛顿仪器的最新发展使单分子操作和分子间及分子内力的测量成为可能。右旋糖酐细丝连接到金表面，用原子力显微镜尖端通过垂直拉伸来探测。在低力作用下，葡聚糖的变形主要受熵力的控制，可以用6埃库恩长度的朗之万函数来描述。在较高的力下，股链的伸长是由键角的扭曲决定的。在更高的力下，葡聚糖细丝发生了明显的构象变化。聚合物变硬，段弹性主要受键角弯曲的影响。构象变化是可逆的，并通过分子动力学计算得到了证实。
Recent developments in piconewton instrumentation allow the manipulation of single molecules and measurements of intermolecular as well as intramolecular forces. Dextran filaments linked to a gold surface were, probed with the atomic force microscope tip by vertical stretching. At low forces the deformation of dextran was found to be dominated by entropic forces and can be described by the Langevin function with a 6 angstrom Kuhn length. At elevated forces the strand elongation was governed by a twist of bond angles. At higher forces the dextran filaments underwent a distinct conformational change. The polymer stiffened and the segment elasticity was dominated by the bending of bond angles. The conformational change was found to be reversible and was corroborated by molecular dynamics calculations.