阐明在epotilone生物合成中cis双键形成的机制
Li Tang1, Shannon Ward, Loleta Chung
1Kosan Biosciences, Inc., 3832 Bay Center Place, Hayward, California 94545, USA. tang@kosan.com
Journal of the American Chemical Society
|January 8, 2004
概括
聚克化合成酶 (PKS) 酶复合物产生D和C等类表皮素.脱水酶域5 (DH5) 对于在这些化合物中产生12,13-cis-双键是必不可少的.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 自然产品的合成自然产品的合成
背景情况:
- 埃波提隆是从Sorangium cellulosum中分离出来的宏环化合物.
- 它们是由模块化聚乙酸合成酶 (PKS) 酶复合体合成的.
- 乙基D和C是前后中间体,具有12,13-cis-双键.
研究的目的:
- 为了研究1213-cis-双键形成的机制,在epothilone生物合成.
- 为了确定产生12,13-cis-双键的特定酶域.
- 阐明在epothilone合成中的模块5 (DH5) 中脱水酶 (DH) 域的作用.
主要方法:
- 在Sorangium纤维素的PKS基因集群的基因操纵.
- 通过改性菌株生产的epotilone中间体的分析.
- 酶域及其活动的生物化学表征.
主要成果:
- PKS的模块4缺乏脱水酶域,但参与形成12,13-双键.
- 在5模块 (DH5) 中DH域的非激活导致了10,11-dehydro-13-hydroxyepothilone D的产生.
- 这证实了DH5对于12,13-脱水阶段是必要的.
结论:
- 脱水酶域5 (DH5) 在形成epothilones中的12,13-cis-双键中起着至关重要的作用.
- 一个涉及域跳转和模块的机制模型解释了DH5的代活动.
- 了解这种机制,可以了解复杂的自然产品的生物合成.
相关概念视频
Peptide Bonds
A peptide bond covalently attaches amino acids through a dehydration reaction. One amino acid's carboxyl group and another amino acid's amino group combine, releasing a water molecule. The resulting bond is the peptide bond. The products that such linkages form are peptides. As more amino acids join this growing chain, the resulting chain is a polypeptide. Each polypeptide has a free amino group at one end. This end has the N-terminal, or the amino-terminal, and the other end has a free...
Preparation of Epoxides
Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
Protein Modifications in the RER
Modification of secretory and transmembrane proteins entering the rough ER begins in the ER lumen. These modifications aid in protein folding and stabilize the acquired tertiary structure. Protein modifications in the rough ER co-occur at different stages of protein folding.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
Epistasis Analysis
Although Mendel chose seven unrelated traits in peas to study gene segregation, most traits involve multiple gene interactions that create a spectrum of phenotypes. When the interaction of various genes or alleles at different locations influences a phenotype, this is called epistasis. Epistasis often involves one gene masking or interfering with the expression of another (antagonistic epistasis). Epistasis often occurs when different genes are part of the same biochemical pathway. The...
Biosynthesis of Nucleic Acids
Nucleic acid biosynthesis is a fundamental biochemical process that produces the purine and pyrimidine nucleotides essential for DNA and RNA synthesis. This pathway maintains a balanced nucleotide pool, preventing imbalances that could jeopardize genetic integrity and cellular function. Given the crucial role of nucleotides, their synthesis is tightly regulated to ensure proper cellular homeostasis.Purine BiosynthesisThe biosynthesis of purine nucleotides begins with ribose-5-phosphate, a...
Production of Pharmaceuticals
Industrial insulin production uses genetically engineered E. coli expressing a proinsulin gene controlled by a tryptophan promoter and containing a methionine linker for later cleavage. The cells also carry ampicillin resistance for selective growth. Seed cultures are stored at −80 °C and production begins by thawing a small amount to inoculate starter cultures, which are progressively scaled to a 50,000-L bioreactor. In the bioreactor, E. coli grow in nutrient-rich media under sterile, tightly...


