代谢工程的发展及其应用

本首先论述了代谢工程的代谢网络理论、代谢分析、节点分析和中心代谢物作用机理等代谢工程理论基础。然后,分析了代谢工程的各种具体设计思路,并以实际例子作了详细说明。另外还对代谢工程的新兴研究方向－逆代谢工程进行了简单说明。     

代谢工程——生物工程学科的新兴研究领域

代谢工程包括推理性代谢工程及逆代谢工程。针对限制生物活性的因素 ,从不同的途径设计代谢改变策略 ,采用重组DNA技术解除或削弱该影响 ,提高目的产物的产率 ,是生化工程学科提高生物活性的新兴研究领域。讨论了推理性代谢工程及逆代谢工程的设计及应用。     

紫杉二烯人工酵母的代谢组学分析

为了更深入地从代谢角度研究萜类合成人工酵母的内在差异,以紫杉二烯人工酵母为例,利用代谢组学的方法对其发酵指数中期胞内代谢物的变化进行了测定。结果表明,与对照菌W303-1A相比,紫杉二烯的生产会对胞内糖酵解、三羧酸循环中间物及一些氨基酸的含量产生不同程度的影响,进而对其生长产生一定抑制作用。其中柠檬酸因紫杉二烯功能模块的引入下降明显,降幅达90%以上,因此可以作为后续功能酵母研究的标志性代谢物。紫杉二烯人工酵母细胞代谢组的研究可以为萜类化合物异源合成的优化提供更多的信息和帮助。     

植物代谢工程的研究现状

植物代谢工程是一个很有发展前景的新兴学科。它可通过多种方法对植物的代谢流进行改造,如加速限制步骤的反应,改变分叉代谢途径的流向,构建代谢旁路,引入转录调节因子、信号因子、植物激素合成基因,扩展和构建新的代谢途径等方法进行。并取得了一些有意义的研究结果。     

代谢网络刚性与代谢工程

本文介绍了有关代谢网络,网络刚性和代谢工程的基本观点,特别是关于网络刚性和载流途径的工作假设,还讨论了代谢工程的应用与面临的难题。     

代谢工程在D-核糖生产中研究现状及应用前景

简要介绍了代谢工程的进展情况,并较为详细地从宿主的选择、加速限速反应、改变代谢流和生产过程的优化等方面论述了代谢工程在D-核糖基因工程菌构建方面的应用及其应用前景。     

聚酮类化合物生物合成的代谢工程研究进展

聚酮化合物是一类重要的具有生物活性的次级代谢物。本文讨论了以聚酮生物合成酶为核心的聚酮化合物生物合成途径,以及近年来有关代谢工程在聚酮类化合物生物合成方面的研究工作进展,主要包括将聚酮生物合成途径引入新的宿主、代谢流量分析在提高聚酮化合物中的应用及合成新的聚酮化舍物等。     

Rational design of thiolase substrate specificity for metabolic engineering applications

Metabolic engineering efforts require enzymes that are both highly active and specific toward the synthesis of a desired output product to be commercially feasible. The 3‐hydroxyacid (3HA) pathway, also known as the reverse β‐oxidation or coenzyme‐A‐dependent chain‐elongation pathway, can allow for the synthesis of dozens of useful compounds of various chain lengths and functionalities. However, this pathway suffers from byproduct formation, which lowers the yields of the desired longer chain products, as well as increases downstream separation costs. The thiolase enzyme catalyzes the first reaction in this pathway, and its substrate specificity at each of its two catalytic steps sets the chain length and composition of the chemical scaffold upon which the other downstream enzymes act. However, there have been few attempts reported in the literature to rationally engineer thiolase substrate specificity. In this study, we present a model‐guided, rational design study of ordered substrate binding applied to two biosynthetic thiolases, with the goal of increasing the ratio of C6/C4 products formed by the 3HA pathway, 3‐hydroxy‐hexanoic acid and 3‐hydroxybutyric acid. We identify thiolase mutants that result in nearly 10‐fold increases in C6/C4 selectivity. Our findings can extend to other pathways that employ the thiolase for chain elongation, as well as expand our knowledge of sequence–structure–function relationship for this important class of enzymes.     

代谢工程

代谢工程,也称途径工程,是基因工程一个重要分支,一般是多基因的基因工程,与细胞的基因调控、代谢调控和生化工程密切相关。讨论了代谢工程的应用,包括通过改变代谢流和代谢途径提高产量,改善生产过程,构建新的代谢途径和产生新的代谢产物等。     

维生素C生物转化的代谢工程研究

本从代谢工程角度出发,综述维生素C(Vc)生物转化代谢研究进展。分别论述了3条产生Vc重要前体2-酮基-L-古龙酸(2-KLG)反应路线的代谢机制、反应酶系及代谢工程菌构建等方面的问题;并对Vc生物转化应用前景作了展望。     

基因组尺度代谢网络研究进展

基因组尺度代谢网络从基因组序列出发,结合基因、蛋白质、代谢数据库和实验数据,从系统的角度定量研究生命体的代谢过程,了解各个组分之间的相互作用关系。这类网络模型对于生命活动理论研究和优良工程菌的构建都具有重要的理论和实践意义。以下结合作者的实际研究经验,对基因组尺度代谢网络从重构到模拟直至应用进行了较为详细的介绍,并讨论了一些目前存在的难题和未来的研究方向。     

Metabolic perturbation of acrylate pathway in Lactobacillus plantarum

Engineering microbes with heterologous pathway for production of bio-based products has received considerable attention. Reconstituting such non-native pathway in addition to desired product formation often brings an allosteric modulation in enzymes competing at fragile nodes that result in by-product redistribution, in order to retain energy and redox balance. This work, Lactobacillus plantarum engineered with acrylate pathway for propionate production was studied under similar perspectives. Upon expression, the heterologous pathway did not result in propionic acid production under standard glucose concentration of 20?g/L, but 0.01?mM of propionate was formed when grown under low glucose concentration of 1?g/L. Further analysis of secreted metabolites with increased glucose concentration of 10 and 30?g/L remained futile towards propionate formation but showed reorientation in pyruvate metabolism which was related to the control imposed by the host to regulate the hidden constraints caused by gene perturbation. Further, it was ensured that the limitation of supplements did not play any functional role in inhibiting propionic acid synthesis but still followed similar metabolic pattern which was quite unclear though interpreted to certain extent. Thus, the findings gave insights into physiological and metabolic capabilities of Lactobacillus plantarum that at least in principle can be used to enhance the strain performance for increased propionic acid production.     

Systems approaches to succinic acid-producing microorganisms

Succinic acid is a cellular metabolite belonging to the C4-dicarboxylic acid family, and the fermentative production of succinic acid via the use of recombinant microorganisms has recently become the focus of an increasing amount of attention. Considering the difficulty inherent to the direct application of natural succinic acid producers to the industrial process, a variety of systems biology studies have been conducted regarding the development of enhanced succinic acid production systems. This review shows how the metabolic processes of microorganisms, includingEscherichia coli andMannheimia succiniciproducens, have been optimized in order to achieve enhanced succinic acid production. First, their metabolic networks were constructed on the basis of complete genome sequences, after which their metabolic characteristics were estimated viain silico computer modeling. Metabolic engineering strategies were designed in accordance with the results ofin silico modeling and metabolically engineered versions of bothE. coli andM. succiniciproducens have been constructed. The succinic acid productivity and yield obtained using metabolically engineered bacteria was significantly higher than that obtained using wild-type bacteria.     

大肠杆菌细胞工厂的创建技术

大肠杆菌作为一种重要的模式工业微生物,在医药、化工、农业等方面具有广泛的应用.近30年来,多种代谢工程改造的新策略和新技术,被用于设计、构建和优化大肠杆菌化学品细胞工厂,极大地提高了生物法合成化学品的生产速率和产量.文中将从大肠杆菌途径设计、合成途径创建与优化和细胞全局优化三个方面,对大肠杆菌代谢改造起重要推动作用的技...     

微生物合成鸟氨酸的代谢工程研究进展

鸟氨酸是一种非蛋白氨基酸,对氨态氮的排出及解除氨中毒有重要的作用,可用于功能性饮料、减肥保健产品及护肝抗癌药品等,在医疗、保健、食品等领域具有广泛的应用前景。本文系统地总结目前微生物合成鸟氨酸的研究现状,介绍鸟氨酸的分解代谢和合成代谢途径,及其所涉及的关键酶,详细阐述利用代谢工程改造鸟氨酸生产菌的思路,及其所涉及的代谢工程技术和最新研究进展,展望微生物合成鸟氨酸的代谢工程未来发展方向。     

代谢工程：一项不断发展的菌株改造技术

对代谢工程的发展进行了简要回顾,分析了代谢工程发展的推动力,重点评述了本期专栏发表的12篇代谢工程和细胞工厂方面的论文。     

植物糖基转移酶及其在代谢工程中的应用

糖基转移酶催化植物次生代谢物合成,在植物的生长发育过程以及代谢工程应用方面起着重要作用。该文介绍糖基转移酶的基本特性,总结近年来研究植物糖基转移酶基因的克隆与功能分析的方法,详细阐述了微生物中3个C-糖基转移酶基因（UrdGT2、gilGT和iroA）的克隆和功能研究,概括糖基转移酶在代谢工程的研究进展,并展望今后的研究趋势,为植物C-糖基转移酶的生物学功能研究和代谢应用方面提供有益帮助。