在多基酸合成酶模块中对乙基转移酶域交换的机械分析
Marcus Hans1, Andreas Hornung, Agnieszka Dziarnowski
1Department of Chemical Engineering, Stanford University, Stanford, California 94306, USA.
Journal of the American Chemical Society
|May 2, 2003
概括
通过交换域来改变多基合成酶 (PKSs) 会减少产物形成. 这项研究显示,主要原因是合成酶和ACP域的链延长受损,而不是基质特异性的改变.
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:
- I型模块化多基化合成酶 (PKSs) 合成许多多基化物.
- 在PKS中取代域可以改变多基体结构,但往往会减少产物形成.
- 混合PKS模块效率降低的分子基础尚不清楚.
研究的目的:
- 系统地分析6-deoxyerythronolide B合成酶 (DEBS) 中的转移酶 (AT) 域交换对PKS模块功能的影响.
- 阐明混合PKS模块中减少产品形成的分子基础.
主要方法:
- 交换AT域的混合DEBS模块的系统动态分析.
- 对乙-AT形成,乙-CoA:ACP乙转移酶活性和合成酶催化凝结的测定.
- 单个循环研究和有限的蛋白质分解,以探测酶的功能和结构.
主要成果:
- 与野生型DEBS相比,混合动力模块的营业额下降了15-20倍.
- 不同类型的AT域保留了其活动和特异性.
- 通过合成酶 (KS) 和乙烯载体蛋白 (ACP) 域的链延长在混合模块中被显著减弱.
结论:
- 混合PKS模块的主要缺陷不是改变AT域的特异性,而是KS和ACP域的链延长受损.
- 结构上的差异,特别是在KR和ACP领域之间,可能解释了催化效率的降低.
相关概念视频
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Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
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Proteins perform many mechanical functions in a cell. These proteins can be classified into two general categories- proteins that generate mechanical forces and proteins that are subjected to mechanical forces. Proteins providing mechanical support to the structure of the cell, such as keratin, are subjected to mechanical force, whereas proteins involved in cell movement and transport of molecules across cell membranes, such as an ion pump, are examples of generating mechanical force.


