Mechanisms of Size- and Shape-Determination in Supramolecular Structures by Genetic Information

通过遗传信息确定超分子结构的尺寸和形状的机制

• 批准号: 60580206
• 负责人: KATSURA Isao
• 金额: $ 1.15万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1985
• 资助国家: 日本
• 起止时间: 1985 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60580206/
• 关键词: Supramolecular structure; Assembly; Morphogenesis; Bacteriophage; Mutant; 蛋白質工学

This study was performed to elucidate the mechanisms of size- and shape-determination in supramolecular structures by using lambda phage as the material.My previous studies have shown that the major capsid protein gpE can assemble into five classes of structures having various size and shape, depending on the missense mutation it contains. In this study I have clarified the structure-function relationship of gpE and established a material basis for the explanation of the determination mechanisms, through assignment of various mutations in the DNA base sequence. As concrete results, the positions of amber mutations at 43 sites have been determined completely. Moreover, I have sequenced 28 of the 31 missense mutants which produce head-related structures of various size and shape. Among the latter mutants many are substitutions of Ser, Pro or Gly, which suggests that the functional sites of gpE are rich in <beta> -turns located on the surface of the molecule.Our previous work has indicated that the tail length is determined by the length of the "ruler protein" gpH. In this study thirty mutants having deletions of various size in the middle part of this gene were made by in vitro genetic manipulation. Twelve of them were found to produce phage particles with short tails, which shows that tail assembly proceeds in most cases as long as the deletions are in-frame. Of these twelve phage particles two have fragile tail tips, whereas the rest ten are defective in DNA injection. Therefore, the middle part of gpH seems to play an important role in these functions, while it is dispensable in tail assembly. Since the length of the tail tube is roughly proportional to the number of amino acid residues of gpH, the whole molecule of gpH seems to function as a ruler to measure the tail length.

本研究以λ噬菌体为材料，阐明了超分子结构中大小和形状决定的机制，我以前的研究表明，主要衣壳蛋白gpE可以组装成五类具有不同大小和形状的结构，这取决于它所包含的错义突变。在本研究中，我澄清了gpE的结构与功能的关系，并建立了一个物质基础，通过指定的各种突变的DNA碱基序列的决定机制的解释。作为具体结果，完全确定了43个位点的琥珀突变位置。此外，我已经测序了31个错义突变体中的28个，这些突变体产生各种大小和形状的头部相关结构。后者的突变体中有许多是Ser、Pro或Gly的取代，这表明gpE的功能位点丰富，<beta>依次位于分子表面。我们以前的工作表明尾部长度由“统治者蛋白”gpH的长度决定。在这项研究中，30个突变体具有不同大小的缺失在该基因的中间部分，通过体外遗传操作。发现其中12个产生具有短尾的噬菌体颗粒，这表明只要缺失在框内，在大多数情况下尾组装就进行。在这12个噬菌体颗粒中，有两个具有脆弱的尾尖，而其余10个在DNA注射中有缺陷。因此，gpH的中间部分似乎在这些功能中起重要作用，而它在尾部组装中起重要作用。由于尾管的长度与gpH的氨基酸残基数量大致成比例，因此整个gpH分子似乎起到了测量尾长的标尺的作用。

项目成果

桂勲: 化学と生物. 25. 14-22 (1987)

桂宏：化学与生物学。25. 14-22 (1987)

Isao Katsura: "Proteins as Studied by Exchanges of Amino Acid Residues --- A Basis of Protein Engineering" Kagaku to Seibutu. 25. 14-22 (1987)

Isao Katsura：“通过氨基酸残基交换研究蛋白质——蛋白质工程的基础” Kagaku 到 Seibutu。

Isao Katsura: "Structure and Inherent Properties of the Bacteriophage Lambda Head Shell. <VII> . Distribution of the Functional Sites on the Multifunctional Major Head Protein."

Isao Katsura：“噬菌体 Lambda 头壳的结构和固有特性。<VII>。多功能主要头蛋白上功能位点的分布。”

Isao Katsura: "The Ruler Protein of <lambda> Phage" Saibou Kougaku. 5. 175-177 (1986)

Isao Katsura：“<lambda>噬菌体的统治者蛋白质”Saibou Kougaku。

Isao Katsura: Journal of Molecular Biology. 190. 577-586 (1986)

桂功：分子生物学杂志。