从两个二二烯合成酶 (IrTPS2/IrKSL3a) 的功能可塑性到酶进化
Baolong Jin1,2, Kangwei Xu3,2, Juan Guo1,2
1State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China.
概括
像IrKSL3a和IrTPS2这样的合成酶 (TPS) 呈现出不同的产品形成. 研究人员在IrTPS2中确定了关键的残留物,使其能够添加水,工程IrKSL3a产生新的基化类.
科学领域:
- 生物化学 生化学
- 自然产品化学 自然产品化学
- 酶学 是一种酶学.
背景情况:
- 类是通过合成酶 (TPSs) 合成的多种天然产品.
- TPS酶催化复杂的碳酸级联反应,但火机制往往不清楚.
- 来自Isodon rubescens的IrKSL3a和IrTPS2,尽管具有很高的序列同质性,但表现出不同的催化策略.
研究的目的:
- 为了阐明在IrTPS2中添加水的机制,以形成nezukol.
- 研究特定氨基酸残留在TPS催化活性和产品特异性中的作用.
- 根据机械学的见解,设计IrKSL3a以产生基于机械学的新产品.
主要方法:
- 在IrTPS2.2中关键残留物的位点定向突变发生.
- 多尺度量子力学/分子力学 (QM/MM) 模拟.
- 用工程变体和基因学上多样化的TPS进行酶分析.
主要成果:
- 在IrTPS2中确定了一种氨酸和氨酸残留物,这对结和添加水至关重要.
- 证明β-甲基侧链的固体阻碍可以阻止水的结合.
- 成功设计了IrKSL3a来生产nezukol和其他基化产品.
- 表明已识别的残留物是必要的,但不足以有效地添加水在其他烯合成酶类 (KSL) TPSs.
结论:
- 特定的氨基酸残留决定了密切相关的TPS酶的独特催化机制.
- 机理性理解使酶工程能够改变产品配置文件.
- 进化压力已经塑造了TPS酶以形成特定的产品,例如nezukol合成.
相关概念视频
Overview of Transposition and Recombination
16.1K
Transposons make up a significant part of genomes of various organisms. Therefore, it is believed that transposition played a major evolutionary role in speciation by changing genome sizes and modifying gene expression patterns. For example, in bacteria, transposition can lead to conferring antibiotic resistance. Movement of transposable elements within the genetic pool of pathogenic bacteria can aid in transfer of antibiotic-resistant genetic elements. In eukaryotes, transposons can carry out...
16.1K
Regulation of the Unfolded Protein Response
2.6K
Inositol-requiring kinase one or IRE1 is the most conserved eukaryotic unfolded protein response (UPR) receptor. It is a type I transmembrane protein kinase receptor with a distinctive site-specific RNase activity. As the binding mechanics of the misfolded proteins with the N-terminal domain of IRE-1 are unclear, three binding models — direct, indirect, and allosteric -- are proposed for receptor activation. Nevertheless, it is known that once a misfolded protein associates with IRE1, it...
2.6K
Riboswitches
8.5K
Riboswitches are non-coding mRNA domains that regulate the transcription and translation of downstream genes without the help of proteins. Riboswitches bind directly to a metabolite and can form unique stem-loop or hairpin structures in response to the amount of the metabolite present. They have two distinct regions – a metabolite-binding aptamer and an expression platform.
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...
8.5K
Bacterial RNA Polymerase
30.4K
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
30.4K
Conservative Site-specific Recombination and Phase Variation
6.1K
Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...
The recognition sites for Cre recombinase called LoxP...
6.1K
Transduction
116
Among the three main modes of HGT—transformation, conjugation, and transduction—transduction is unique in that it is mediated by bacteriophages, or bacterial viruses.Transduction occurs in two ways. Generalized transduction occurs during the lytic cycle of a bacteriophage infection. In this process, bacteriophages infect bacterial cells, replicate within them, and ultimately cause cell lysis, releasing newly assembled virions. Occasionally, random fragments of the bacterial genome...
116


