高分子 Vol.63 No.6
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特集 高分子で「生物」をつくる
展望 COVER STORY: Highlight Reviews
Design and Construction of an Artificial Cell
市橋 伯一・四方 哲也
Norikazu ICHIHASHI, Tetsuya YOMO
<要旨> 天然の細胞のもつ機能を試験管内で再構築する試みは、生物を今までとは異なる角度から理解することができ、さらに新しいテクノロジーをもたらすと期待されている。本稿ではこれまでに行われた再構築の試みを紹介し、天然の細胞と同等な機能をもつ人工細胞がデザイン可能なのか、いまだ足りない知識は何なのかを議論する。
Keywords: Design / Construction / Artificial Cell
Cell-Free Protein Synthesis System
松林 英明・上田 卓也
<要旨>無細胞タンパク質合成系は、翻訳機構の解析やタンパク質調製のツールとして用いられるほか、近年では、人工細胞モデル構築をはじめとした合成生物学の基盤技術としても応用されている。本稿では、再構築型無細胞タンパク質合成系として筆者らが開発、改良してきたPURE systemを中心に、無細胞タンパク質合成系の概要と今後の展望について紹介したい。
Keywords: Cell-Free System / Translation / PURE System / Protein Maturation / Unnatural Amino Acids / Ribosome Display
Chemical Construction of Artificial-Cell
菅原 正・鈴木健太郎
Tadashi SUGAWARA, Kentaro SUZUKI
Keywords: Giant Vesicle / Artificial Cell / DNA Amplification / Self-reproduction / Vesicular Transport
トピックス COVER STORY: Topics and Products
Synthetic RNA Technologies to Control molecular Information and Structure
齊藤 博英
Hirohide SAITO
<要旨> Research in the synthetic biology field, which attempts to bring about new technologies by understanding life through the process of “artificially creating” biomolecules and biological systems, is becoming established worldwide. Creating artificial biomolecules that freely control the functions of living cells and applying them to examinations and medical treatments is one of the research goals of this new field. We will use the unique synthetic RNA technologies to tackle these issues. For example, we have succeeded in developing “synthetic RNA switches” that can control translation of desired genes in target mammalian cells. We have also developed a method to control cell fate by using protein-responsive RNA translational ON/OFF switches. Moreover, for the first time we have succeeded in designing and constructing synthetic RNA-protein complexes (RNP)-based nanostructures, providing great potential for nanomedicine and biotechnology applications.
Keywords: RNA / Synthetic Biology / Translation / RNP / Nanotechnology / Human Health Care
Self-Organization in Cell-Scale Nonequilibrium Systems: Spontaneous Motions and Oscillatory Reactions
瀧ノ上 正浩
<要旨> In natural living systems, we find self-organized dynamic phenomena such as cellular tactic motion, cell division, pattern formation of animal body surface, beating of heart, circadian rhythm, etc. Amazingly, all the dynamic phenomena are realized by autonomous molecular reactions. In general, these phenomena are known to occur in nonequilibrium open systems, which have sustained influx and dissipation of matter and energy into/out of the systems. In recent years, autonomous and dynamic molecular systems such as artificial cells and molecular robots have been developed by learning from the nonequilibrium self-organized phenomena of living systems. Using these molecular systems, we can accelerate understanding of dynamic properties of living systems, and also achieve highly functionalized micro/nano-scaled molecular devices. In this topic, I describe two cell-sized nonequilibrium self-organized phenomena: (i) autonomous motion of cell-sized objects and (ii) spontaneous chemical oscillation in a cell-sized reaction system. We believe that these basic studies will be applied to more complex and highly functionalized molecular systems in the future.
Keywords: Artificial cell / Nonequilibrium / Self-Organization / Molecular Robot / Water-in-Oil Microdroplet
In vitro微小血管モデル:生体組織構造のデザイン
In vitro Microvasculature Models: Designing Living Tissue Structures
松永 行子
<要旨>Conventional preclinical drug evaluation models include a lack of similarity between two-dimensionally cultured systems and in vivo systems, and a discrepancy between animal models and human models. Microtechnologies is a powerful tool to mimic the microenvironment (i.e. chemical and mechanical properties) of the tissues. Therefore, the concept of organ-on-chips was recently proposed to establish in vitro models that precisely recapitulate in vivo characteristics as well as drug response. Here we explain a importance of in vitro tissue models and organ-on-chips, and emphasize need for the in vitro microvasculature models that are deeply involved in various organ/tissue events such as inflammation, metabolism and regeneration.
Keywords: Tissue Engineering / Microfabrication / Microvasculature / Collagen Gel
Why 20 Amino Acids?
網蔵 和晃・木賀 大介
Kazuaki AMIKURA, Daisuke KIGA
<要旨>It is generally accepted that primitive genetic codes employed fewer than 20 amino acids. In other words, biochemistry in a primitive cell was realized by using simplified proteins including only the amino acids that were considered to be used in primitive genetic codes. We wonder whether it is possible to construct such biochemical systems using simplified proteins. In this paper, we will describe previous studies about the number of amino acids in genetic codes and introduce our research in order to answer the question. In our recent study for construction of simplified genetic code, codons for amino acids are reassigned to alanine or serine to reduce a number of amino acids in the engineered code. Simplified genetic codes will provide an effective tool for construction of simplified proteins (A. Kawahara-Kobayashi, et al., Nucl. Acids Res, (2012), K. Amikura, et al., RSC advances, (2013)).
Keywords: Amino Acids / Genetic Code / tRNA / Protein / Evolution / Engineering / Origin of Life
Genetic Alphabet Expansion and its Application
平尾 一郎・木本 路子・松永 賢一郎
Ichiro HIRAO, Michiko KIMOTO, Ken-ichiro MATSUNAGA
<要旨>Expansion of the genetic alphabet by an unnatural base pair system could provide a powerful platform for new biotechnology. Recently, we developed unnatural base pairs that exhibit high fidelity in replication as a third base pair, and applied them to an evolutionaly engeneering method. Through the application, we succeeded in the generation of high affinity DNA aptamers containing unnatural bases and proved that unnatural bases significantly augment nucleic acid functionalities.
Keywords: Unnatural Base Pair / Genetic Alphabet Expansion / PCR / DNA Aptamer
グローイングポリマー Polymer Science and I: A Personal Account
To Make Own Skill
金 善南
Sunnam KIM
<要旨> With new idea and own skill, we can develop a new technology. New idea comes up for advanced life with solving inconvenience. To make own skill, we need to make an effort with special training and knowledge. Also, communication with nearby professionals is very helpful.
高分子科学最近の進歩 Front-Line Polymer Science
Ultrasmall Metal Clusters with Unusual Structures and Properties
小西 克明
Katsuaki KONISHI
<要旨> Subnanometer-sized noble metal clusters with defined nuclearity have recently attracted special attention in relation to their unique optical(electronic absorption / luminescence)properties arising from their molecular-like characters. In this article, recent progresses in structure determination of ultrasmall gold and silver clusters by X-ray crystallography is summarized. An example is provided by the crystal structure of thiolate-capped Ag44 cluster, which has a Keplerate-type double-structured silver core and is markedly different from those of the related gold clusters with similar nuclearity. Examples of several diphosphine-coordinated non-spherical gold clusters with core+exo type geometries and their unique optical properties are also presented. Unlike conventional spherical clusters, they exhibit isolated visible absorption bands, indicating that the attachment of metal atoms drastically alters the electronic structures of the cluster moiety.
Keywords: Metal Cluster / Gold / Silver / Crystal Structure / Optical Properties / Geometry