对LsrK激酶所需的机械洞察力,用于自诱导-2定数感应激活
Jie Zhu1, Mark S Hixon, Daniel Globisch
1The Skaggs Institute for Chemical Biology and Department of Chemistry and the Worm Institute for Research and Medicine (WIRM), the Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037, USA.
Journal of the American Chemical Society
|May 16, 2013
概括
研究人员特征了激酶LsrK,这对于细菌的定数感应至关重要. 他们阐明了它的动力机制和基质相互作用,为向致病性细菌提供了基础.
科学领域:
- 生物化学 生物化学
- 微生物学 微生物学
- 酶学 是一种酶学.
背景情况:
- LsrK是肠道细菌中的一个关键酶,用于II型定数感应 (AI-2) 的4,5-二基-2,3-二 (DPD) 的酸化.
- 这种酸化对于AI-2细胞质封存和调节AI-2相关基因在细菌定数组发育中至关重要.
- 在此之前,LsrK的动态细节对于DPD定数感应系统至关重要,并未报告.
研究的目的:
- 为了确定LsrK酶的稳定状态动力学参数.
- 为了阐明LsrK催化酸化的动力机制.
- 调查LsrK与DPD的基质概况,并确定潜在的调节分子标.
主要方法:
- 开发用于测量LsrK活动的持续UV-VIS光谱测定方法.
- 使用ATP和DPD作为基质进行平稳状态运动分析.
- 用各种DPD类似物进行LSrK的基质分析.
主要成果:
- 确定动力机制是快速平衡的,ATP首先结合.
- 确定了关键的动力参数:kcat (7.4 ± 0.6 s-1),Km,ATP (150 ± 30 μM) 和Km(app),DPD (1.0 ± 0.2 mM).这些参数包括:kcat (7.4 ± 0.6 s-1),Km,ATP (150 ± 30 μM) 和Km(app),DPD (1.0 ± 0.2 mM).
- 在基于细胞的记者试验和关于DPD基质活性的LSRK酶试验之间观察到一种生物化学断开.
结论:
- 这项研究提供了LsrK的第一个动力特征,揭示了它的机制和参数.
- 这些发现突显了lsrK的重要性,并为设计能够抑制病原体AI-2定数感应的分子提供了基础.
- 观察到的基质形状差异要求对AI-2信号通路进行进一步调查.
相关概念视频
Gene Regulation in Microbial Communities: Quorum Sensing
Quorum sensing is a mechanism of bacterial communication that enables coordinated gene expression in response to changes in population density. This facilitates collective behaviors that enhance survival, resource acquisition, and ecological adaptation. This process relies on small signaling molecules called autoinducers that accumulate as bacterial populations grow. When a critical threshold concentration of autoinducers is reached, bacterial cells collectively modify gene expression,...
Bacterial Signaling
Bacterial signaling can occur within bacteria (intracellular) or between bacteria (intercellular). At times, a group of bacteria behaves like a community. To achieve this, they engage in quorum sensing, the perception of higher cell density that causes changes in gene expression. Quorum sensing involves both extracellular and intracellular signaling. The signaling cascade starts with a molecule called an autoinducer (AI). Individual bacteria produce AIs that move out of the bacterial cell...
Cell Signaling in Plants
Plant cells communicate to coordinate their cycle of growth, flowering and fruiting, and activities in roots, shoots, and leaves in response to the changing environmental conditions. Plant signaling is distinct from animal signaling. Plants primarily utilize enzyme-linked receptors, whereas the largest class of cell-surface receptors in animals are G-protein coupled receptors (GPCRs). Unlike animals, receptor tyrosine kinases are rare in plants. Instead, plants have a diverse class of...
Inducible Operons: lac Operon
The lac operon in Escherichia coli is a model for understanding inducible gene regulation and metabolic flexibility. It integrates local control by lactose and global regulation through catabolite repression, enabling E. coli to preferentially metabolize glucose when available and switch to lactose utilization when glucose is scarce.Structure and Function of the lac OperonThe lac operon contains three structural genes: lacZ (β-galactosidase), lacY (lactose permease), and lacA (thiogalactoside...
MAPK Signaling Cascades
Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
Global Regulatory Systems
Global regulatory systems in bacteria enable rapid and coordinated responses to environmental changes by integrating sensory inputs with gene expression, ensuring efficient adaptation to fluctuating conditions. Key global regulatory mechanisms include regulons, two-component systems, sigma factors, and secondary messengers.Regulons and Global RegulatorsA regulon is a collection of genes and operons controlled by a common global regulator. These regulators enable bacteria to prioritize resource...


