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arXiv physics/9911041physics.bio-phq-bio
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论手性的生物学优势

On the Biological Advantage of Chirality

G. Gilat

摘要:

在生命的主要分子中,手性的存在很可能不仅仅是一种结构上的人工产物,而是纯粹的生物学优势。存在一种特殊的相互作用模式的现象的可能性,被标记为“手性相互作用”(CI),其中结构手性是必要条件,是这种优势的主要原因。为了证明这种可能性,宏观手性设备的介绍,并提出了这样的相互作用的类比。为此,重要的是要明确区分几何和物理手性,后者能够与各种介质进行手性相互作用。除了手性之外,还需要一些其他的结构元素。特别是,存在手性器件和与其相互作用的介质之间的界面。物理手性是建立在这个手性相互作用发生的界面上的。在分子水平上,特别是可溶性蛋白质,活性介质是在水性溶剂中存在随机离子运动。作为手性相互作用的结果,产生了一定的扰动或电流,并沿着$ α$ -螺旋结构的线圈在两个可能的方向中的一个优选方向上流动。这样的手征相互作用的模型,并指出了一些重要的后果。特别是,重要的是要强调手性相互作用的时间不可逆特征,这导致其非遍历性质,这被认为是生物分子进化过程的必要条件。Careri等人的实验结果表明,蛋白质水合层中的自由质子运动与其酶活性之间存在明显的联系。

英文摘要:

The presence of chirality in the main molecules of life may well be not just a structural artifact, but of pure biological advantage. The possibility of the existence of a phenomenon of a special mode of interaction, labeled as "chiral interaction" (CI), for which structural chirality is a necessary condition, is the main reason for such an advantage. In order to demonstrate such a possibility, macroscopic chiral devices are introduced and presented as analogies for such an interaction. For this purpose it is important to make a clear distinction between geometric and physical chiralities, where the latter are capable to perform chiral interactions with various media. Apart from chirality, a few other structural elements are required. In particular, the presence of an interface that separates between the chiral device and the medium with which it is interacting. The physical chirality is build into this very interface where chiral interaction is taking place. On a molecular level, soluble proteins in particular, the active medium is the presence of random ionic motion in the aqueous solvent. As a result of chiral interaction a certain perturbation, or current, is generated and flowing along the coils of $ α$-helix structure in one preferred direction out of two possible ones. A model for such a chiral interaction is presented and a few significant consequences are pointed out. In particular, it is important to emphasize the time-irreversible feature of chiral interaction, which leads to its non-ergodic nature that is to be considered a necessary condition for evolutionary processes in biomolecules. There exists an experimental result by Careri et al. who found a clear linkage between the free protonic motion in the hydration layer of protein s and their enzymatic activity.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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