对于真菌PKS-NRPS杂交的还原性域具有类似于铁酶的作用
1Department of Medicinal Chemistry, University of Utah, 30 South 2000 East Rm 201, Salt Lake City, Utah 84112, USA.
Journal of the American Chemical Society
|July 26, 2008
概括
菌酶产生各种分子,但pyrrolidine-2-one环形形成被误解. 乙合成酶R域催化了迪克曼凝聚,而不是减少,揭示了对多基基生物合成的新见解.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 酶学 是一种酶学.
背景情况:
- 菌多基体表现出结构多样性,通常具有四酸或pyrrolidine-2-one末端组.
- 罗利丁-2-one的多样性与特定的酶域有关,在四酸合成酶中具有C-终端还原 (R) 域,此前假设可以促进它们的释放.
研究的目的:
- 阐明导致真菌中罗利丁-2-one结构多样化的酶机制.
- 为了研究equisetin合成酶 (EqiS) 的C端R域的功能.
主要方法:
- 过度表达的等合成酶 (EqiS) R域.
- 使用合成基质类似物进行酶分析以分析反应性.
- 动力分析以确定催化效率 (kcat).
主要成果:
- EqiS R域不表现出降解活性,也不结合常见的降解辅因子.
- EqiS R 域催化了迪克曼凝结反应.
- 估计EqiS R域的催化速率 (kcat) 约为15秒 (-1).
结论:
- EqiS R 域的功能不同于拟议的还原作用和短链脱酶/还原酶超级酶典型的氧化还原反应.
- 这一发现修订了对真菌聚基化物生物合成中的罗利丁-2-形成的理解,突出了非还原性催化机制.
相关概念视频
Sulfur Assimilation
Sulfur is an essential element in biological systems, contributing to synthesizing key biomolecules, including amino acids such as cysteine and methionine, and cofactors such as coenzyme A and biotin. Microorganisms primarily assimilate sulfur as sulfate (SO₄²⁻) from the environment, which must undergo a series of biochemical transformations before it can be incorporated into cellular components. As sulfate is highly oxidized, it must undergo assimilatory sulfate reduction to become...
Riboswitches
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...
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.
Conservative Site-specific Recombination and Phase Variation
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...
Ribozymes
The term ribozyme is used for RNA that can act as an enzyme. Ribozymes are mainly found in selected viruses, bacteria, plant organelles, and lower eukaryotes. Ribozymes were first discovered in 1982 when Tom Cech’s laboratory observed Group I introns acting as enzymes. This was shortly followed by the discovery of another ribozyme, Ribonulcease P, by Sid Altman’s laboratory. Both Cech and Altman received the Nobel Prize in chemistry in 1989 for their work on ribozymes.
Ribozymes can be...
Ribozymes can be...
Protein Complexes with Interchangeable Parts
Groups of proteins may form a complex where each protein in this complex has a different role in the overall execution of the complex’s function. Often some of the proteins in the complex can be replaced by a closely related variant to give a complex that contains many of the same components yet is functionally distinct.
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order to...


