Elasticity theory for self-assembled protein lattices with application to the martensitic phase transition in bacteriophage T4 tail sheath
Elasticity theory for self-assembled protein lattices with application to the martensitic phase transition in bacteriophage T4 tail sheath
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DOI：
10.1103/physreve.73.011917
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发表时间：
2006-01-01
影响因子：
2.4
通讯作者：
James, RD
中科院分区：
文献类型：
--
作者：
Falk, W;James, RD
我们提出了一个弹性理论的一维和二维阵列的球状蛋白质的相对位置和相对旋转相邻分子之间的自由能的影响。这种组件的运动学描述，相容性的条件被发现，给出的自由能的形式，和公式所施加的力和力矩的开发。它表明，完全放松状态的片材由螺旋变形的片材，其本身是由螺旋链的分子在合理的方向。我们将这一理论应用于病毒噬菌体T4的尾鞘中发生的迷人的收缩变形，这有助于其入侵其细菌宿主。使用电子密度图的扩展和收缩鞘，我们近似的领域，每个分子的椭球体，然后评估我们的公式的位置和方向的每个分子。我们表明，由此产生的运动学描述，扩展和收缩尾鞘的配置产生一个简单的公式。我们提出了一个约束版本的理论的基础上测量的扩展和收缩鞘。根据鲍林的建议[讨论]。法拉第学会13，170（1953）]，我们发展了一个分子相互作用的简单模型。由此产生的自由能被发现具有双阱结构。某些简单的变形进行了研究（拉伸，扭转膨胀），理论预测一阶坡印亭效应和一些意想不到的模量之间的关系。最后，穿透力，并提出了一个可能有趣的计划，这种片的外延生长和图案化。
We propose an elasticity theory for one-and two-dimensional arrays of globular proteins for which the free energy is affected by relative position and relative rotation between neighboring molecules. The kinematics of such assemblies is described, the conditions of compatibility are found, a form of the free energy is given, and formulas for applied forces and moments are developed. It is shown that fully relaxed states of sheets consist of helically deformed sheets which themselves are composed of helical chains of molecules in rational directions. We apply the theory to the fascinating contractile deformation that occurs in the tail sheath of the virus bacteriophage T4, which aids its invasion of its bacterial host. Using electron density maps of extended and contracted sheaths, we approximate the domains of each molecule by ellipsoids and then evaluate our formulas for the position and orientation of each molecule. We show that, with the resulting kinematic description, the configurations of extended and contracted tail sheaths are generated by a simple formula. We proposed a constrained version of the theory based on measurements on extended and contracted sheath. Following a suggestion of Pauling [Discuss. Faraday Soc. 13, 170 (1953)], we develop a simple model of the molecular interaction. The resulting free energy is found to have a double-well structure. Certain simple deformations are studied (tension, torsion inflation); the theory predicts a first-order Poynting effect and some unexpected relations among moduli. Finally, the force of penetration is given, and a possibly interesting program of epitaxial growth and patterning of such sheets is suggested.