基基稳定允许在达罗巴克生物合成过程中形成以太
Austin M Woodard1,2, Francesca Peccati3, Claudio D Navo3
1Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
bioRxiv : the preprint server for biology
|December 11, 2023
概括
研究人员探索了抗生素达罗巴克A的酶修饰,通过改变其前体来创造新的变体. 这项研究揭示了对激素S-adenosyl metionin酶催化物的洞察力,并为未来的脚手架工程提供了信息.
科学领域:
- 生物化学 生物化学
- 合成生物学 合成生物学
- 药用化学 医学化学
背景情况:
- 达罗巴丁A是一种格拉姆阴性选择性抗生素,具有独特的化双循环结构和作用机制.
- 达罗巴克是一种核糖体合成和翻译后修饰的 (RiPP),需要酶成熟.
- 成熟过程涉及一个根性S-adenosyl metionin (rSAM) 依赖酶 (DarE),安装以太和C-C交叉链接.
研究的目的:
- 通过使用各种达罗巴克前体 (DarA) 变体来研究DarE的酶耐受性.
- 为了表征新的达洛巴丁变体,改变了化双循环结构和交叉链接模式.
- 阐明以太与C-C交叉连接形成的机制基础,并确定控制基质参与的关键残留物.
主要方法:
- 使用DarE对57种合成DarA变体进行酶修饰.
- 使用结构和分析技术,对50种酶修饰的达洛巴克丁变体进行了表征.
- 计算分析包括分子对接和过渡状态计算.
- 拟议的中间体的实验验证和DarA领导区域的突变分析.
主要成果:
- 在DarA变种上,DarE表现出酶耐受性,独立地在不同位置安装以太和C-C交叉链接.
- 产生了57种达罗巴克的变种,包括新型结构,如达罗巴克W3Y和达罗巴克K5F,具有融合的双循环和二环模式.
- 计算研究将芳香氨基酸的基结稳定性与以太形成相关联,并支持以太 (Trp-C7) 和C-C (Trp-C6) 交叉链的独特的内极连接性.
- 提供了以太交叉链形成中的β-oxotryptophan中间体的实验证据.
- 突变分析确定了可放弃的残留物和DarE对基质接触的关键决定因素.
结论:
- 在安装以太和C-C交叉链接方面,DarE表现出显著的灵活性,使得各种多巴丁支架的生成成为可能.
- 该研究提供了对rSAM依赖的交叉链接的机制性见解,将基态稳定性与以太形成联系起来.
- 了解DarE的基质参与和催化原理,有助于合理设计达洛巴基架,以实现潜在的治疗应用.
相关概念视频
Radical Reactivity: Steric Effects
1.9K
The presence of electron-donating, electron-withdrawing, or conjugating groups adjacent to a radical center, imparts electronic stabilization to the radicals. Examples of such electronically-stabilized radicals are triphenylmethyl, tetramethylpiperidine‐N‐oxide, and 2,2‐diphenyl‐1‐picrylhydrazyl. These radicals are remarkably stable and are known as persistent radicals. Some of the persistent radicals can even be isolated and purified.
Along with electronic...
Along with electronic...
1.9K
Radical Substitution: Allylic Bromination
5.1K
In organic synthesis, the formation of products can be altered by changing the reaction conditions. For example, a dibromo addition product is formed when propene is treated with bromine at room temperature. In contrast, propene undergoes allylic substitution in non-polar solvents at high temperatures to give 3-bromopropene. In order to avoid the addition reaction, the bromine concentration must be kept as low as possible throughout the reaction. This can be achieved using N-bromosuccinimide...
5.1K
Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism
2.2K
Birch reduction uses solvated electrons as reducing agents. The reaction converts benzene to 1,4-cyclohexadiene. The reaction proceeds by the transfer of a single electron to the ring to form a benzene radical anion. This anion is highly basic—it abstracts a proton from the alcohol to form a cyclohexadienyl radical. Another single electron transfer gives the cyclohexadienyl anion. A proton transfer from the alcohol forms 1,4-cyclohexadiene. Since this reduction occurs via radical anion...
2.2K
Radical Formation: Elimination
1.7K
Another method of radical formation is the elimination process. It is the opposite of the addition route and is driven by the instability of the radical. For example, as depicted in Figure 1, dibenzoyl peroxide yields a pair of unstable radicals upon homolysis. Given its instability, this radical spontaneously undergoes elimination via a C–C bond cleavage to form a relatively more stable phenyl radical. The mechanism involves cleavage of the bond between the α and β positions...
1.7K
E1 Reaction: Stereochemistry and Regiochemistry
9.6K
One of the critical aspects of the E1 reaction mechanism, as also observed in E2, is the regiochemistry, with multiple regioisomers obtained as products. In the example discussed, the presence of water as a weak base favors elimination over substitution to generate two alkenes. Given that alkenes’ stability increases with the number of alkyl groups across the double bond, typically, E1 reactions lead to the Zaitsev product, for this is more substituted and stable than the Hofmann product.
9.6K
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
3.4K
Malonic ester synthesis is a method to obtain α substituted carboxylic acids from ꞵ-diesters such as diethyl malonate and alkyl halides.
3.4K


