EVOLUTIONARILY MOBILE MODULES IN PROTEINS
EVOLUTIONARILY MOBILE MODULES IN PROTEINS
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DOI：
10.1038/scientificamerican1093-50
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发表时间：
1993-10-01
影响因子：
3
通讯作者：
BORK, P
中科院分区：
文献类型：
--
作者：
DOOLITTLE, RF;BORK, P
近几十年来，分子生物学家和生物化学家已经了解到，许多蛋白质是由结构域或离散的氨基酸块组成的。这些结构域中的许多具有有助于蛋白质的总体活性的明确功能。此外，在进化过程中，这些模块单元中的一些经常在蛋白质内部和蛋白质之间移动。这些模块的进化移动性并不局限于单一物种遗传物质中的啤酒花：在某些情况下，这些模块显然能够横向跨越物种线，甚至从动物细胞移动到细菌。由于在编码蛋白质的基因区域也发现了区室划分，许多生物学家相信这些结构特征是同一潜在现象的反映。他们相信每个基因编码区对应于蛋白质的一个特殊结构特征。我们和我们的同事持不同的观点。在我们看来，证据的分量福尔斯落在这样一个论点上，即按照进化的标准，基因被细分为独立的编码部分是一个最近的发展，蛋白质是由称为氨基酸的小分子组成的长链。20种不同的氨基酸，每一种都有自己的形状和化学特性，构成了自然界中发现的所有蛋白质。蛋白质的所有性质都取决于20种氨基酸中的哪一种用于其结构，特别是它们连接在一起的顺序。最值得注意的是，氨基酸序列决定了蛋白质如何折叠成一个活跃的三维体。
Eolecular biologists and bio-chemists have learned in recent decades that many proteins consist of domains, or discrete blocks of amino acids. Many of these domains have well-de ‘ned functions that contribute to the overall activity of a protein. Furthermore, some of these modular units frequently move about within and between proteins during evolution. The evolutionary mobility of these modules is not restricted to hops within the genetic material of a single species: in some cases, the modules are apparently able to travel laterally across species lines» even moving from animal cells to bacteria, for example. Because a compartmental delineation has also been found in the regions of genes that encode proteins, many biologists have been convinced that these structural features are re’ections of the same underlying phenomenon. They believe that each genetic coding region corresponds to a speci ‘c structural feature in a protein. We and our colleagues take a somewhat di” erent point of view. The weight of evidence, in our opinion, falls to the argument that the subdivision of genes into separate coding parts is a far more recent development by evolutionary standards.Proteins are long chains of small molecules called amino acids. Twenty different kinds of amino acids, each with its own shape and chemical character, make up all the proteins found in nature. All the properties of a protein depend on which of the 20 amino acids are used in its construction and, particularly, on the order in which they are strung together. Most notably, the amino acid sequence determines how the protein will fold up into an active, threedimensional body.