监测碳水化合物聚合酶的过程性和长度控制
Matthew R Levengood1, Rebecca A Splain, Laura L Kiessling
1Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
Journal of the American Chemical Society
|July 12, 2011
概括
研究了GlfT2,这是Mycobacterium结核病细胞壁合成的关键酶. 研究人员使用了一种新的质谱测试方法,发现GlfT2作为一个过程聚合酶,连续添加单体,以控制银河系链的延长.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 微生物学 微生物学
背景情况:
- 碳水化合物聚合酶对于生物过程至关重要,但它们的聚合机制在很大程度上仍未被阐明.
- 了解酶机制,如过程式与分布式链延长,是基本的.
- GlfT2对于Mycobacterium结核病细胞壁生物合成至关重要,催化银河系形成.
研究的目的:
- 确定 GlfT2.2 的聚合机制 (渐进或分布式).
- 为了研究GlfT2对聚合物长度的控制的分子基础.
- 探索GlfT2.2的催化机制和运动性质.
主要方法:
- 开发一种使用稳定同位素标记受体的质谱测试方法.
- 在实验室中用重组GlfT2和合成受体进行聚合分析.
- 动力分析以探测基质结合和聚合效率.
主要成果:
- GlfT2被证明是一个过程聚合酶,通过连续的单体添加来维持基质接触.
- 重组GlfT2表现出对聚合物长度的内在控制,产生类似于内源结构的银河系链.
- 有证据表明,GlfT2具有d-galactofuranose (Galf) 结合的子位点,有助于高效的过程聚合和动态滞后阶段.
结论:
- GlfT2在Mycobacterium tuberculosis中采用了一种过程性机制来合成银河.
- 酶控制聚合物长度的能力是固有的,并与基质结合子站点相关.
- 开发的质谱方法适用于研究其他碳水化合物聚合机制.
相关概念视频
The Replisome
DNA replication is carried out by a large complex of proteins that act in a coordinated matter to achieve high-fidelity DNA replication. Together this complex is known as the DNA replication machinery or the replisome.
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
Lagging Strand Synthesis
During replication, the complementary strands in double-stranded DNA are synthesized at different rates. Replication first begins on the leading strand. Replication starts later, occurs more slowly, and proceeds discontinuously on the lagging strand.
There are several major differences between synthesis of the leading strand and synthesis of the lagging strand. 1) Leading strand synthesis happens in the direction of replication fork opening, whereas lagging strand synthesis happens in the...
There are several major differences between synthesis of the leading strand and synthesis of the lagging strand. 1) Leading strand synthesis happens in the direction of replication fork opening, whereas lagging strand synthesis happens in the...
Proofreading
Synthesis of new DNA molecules is carried out by the enzyme DNA polymerase, which adds nucleotides on the daughter strand complementary to the template DNA strand. DNA polymerase has a higher affinity to add the correct base and ensures fidelity during DNA replication. Furthermore, it exhibits proofreading activity during replication, using an exonuclease domain that cuts off incorrect nucleotides from the nascent DNA strand.
Errors During Replication are Corrected by the DNA Polymerase Enzyme
Errors During Replication are Corrected by the DNA Polymerase Enzyme
Proofreading
Overview
Translesion DNA Polymerases
Translesion (TLS) polymerases rescue stalled DNA polymerases at sites of damaged bases by replacing the replicative polymerase and installing a nucleotide across the damaged site. Doing so, TLS allows additional time for the cell to repair the damage before resuming regular DNA replication.
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
Eukaryotic RNA Polymerases
RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional similarities. Among the three eukaryotic RNAPs, RNA Polymerase II is most similar to bacterial RNAP in terms of both structural organization and folding topologies of the enzyme subunits. However, these similarities are not reflected in their mechanism of action.
All three eukaryotic RNAPs require specific transcription factors, of which the...
All three eukaryotic RNAPs require specific transcription factors, of which the...


