モー依存性窒素酵素の活性部位の熱力学的景観を確立する
David P Hickey1, Rong Cai1, Zhi-Yong Yang2
1Department of Chemistry , University of Utah , Salt Lake City , Utah 84112 , United States.
Journal of the American Chemical Society
|October 3, 2019
まとめ
窒素酵素は窒素ガス (N2) をアンモニア (NH3) に変換する. この研究では,生理学的条件下で生物学的窒素固定に不可欠なエンドルゴン電子移転のステップを測定した.
科学分野:
- 生物化学
- バイオ電気化学
- 酵素触媒
背景:
- 窒素酵素は大気中の窒素 (N2) をアンモニア (NH3) に変換する.
- モリブデン依存ニトロゲンゼは,3つのメタロコファクター間の複雑な電子移転を伴う.
- 生理学的条件下における窒素酵素共因子の熱力学は十分に理解されていない.
研究 の 目的:
- 窒素化メタルコファクターの還元力を直接測定する.
- 窒素固定中の電子移転の熱力学的風景を解明する.
- 活性サイトポテンシャルを調節するナイトロゲンリデクタズの役割を理解する.
主な方法:
- ピレン改変ヒドロゲルを用いて,触媒性窒素酶タンパク質を電極に固定する.
- 直接的なポテンシャル測定のための電酵素インターフェースの開発.
- メタロコファクター還元ポテンシャルの電気化学分析
主要な成果:
- 窒素酶の電気酵素インターフェースを成功裏に確立した.
- 各メタルコファクターの直接測定された還元ポテンシャル.
- N2還元における電子移転のステップは生理学的条件下でエンダーゴニックであることを実証した.
結論:
- この研究は,窒素酵素の機能に関する重要な熱力学的データを提供します.
- 活性部位の電気化学的潜在力を変化させるのに重要な役割を果たします.
- これらのエンダーゴニックプロセスを理解することは,人工窒素固定戦略にとって不可欠です.
さらに関連する動画
08:05Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
Published on: October 7, 2020
6.5K
09:42Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes
Published on: January 16, 2016
9.3K
関連する概念動画
Inorganic Nitrogen Assimilation
421
Nitrogen is an essential element in biological systems, forming a crucial component of proteins, nucleic acids, and other cellular constituents. Many bacteria and archaea acquire nitrogen in the form of nitrate (NO₃⁻) or ammonia (NH₃), which are then assimilated into biomolecules through specific enzymatic pathways.Assimilatory Nitrate ReductionWhen nitrate enters the cell, it undergoes a two-step reduction process known as assimilatory nitrate reduction. Initially, the enzyme...
421
Metabolism of Chemolithotrophs
707
Chemolithotrophs are microorganisms that obtain energy by oxidizing inorganic molecules such as hydrogen gas (H₂), ammonia (NH₃), reduced sulfur compounds (H₂S, S²⁻), and ferrous iron (Fe²⁺). Unlike heterotrophic organisms that rely on organic carbon, chemolithotrophs transfer electrons from these inorganic donors to the electron transport chain (ETC), generating a proton motive force (PMF) that drives ATP synthesis through oxidative phosphorylation.
707
Thermodynamics: Chemical Potential and Activity
1.6K
The effective concentration of a species in a solution can be expressed precisely in terms of its activity. Activity considers the effect of electrolytes present in the vicinity of the species of interest and depends on the ionic strength of the solution. The activity of a species is expressed as the product of molar concentration and the activity coefficient of the species.
The thermodynamic equilibrium constant is more accurately defined in terms of activity rather than concentration.
The thermodynamic equilibrium constant is more accurately defined in terms of activity rather than concentration.
1.6K
Arrhenius Plots
46.4K
The Arrhenius equation relates the activation energy and the rate constant, k, for chemical reactions. In the Arrhenius equation, k = Ae−Ea/RT, R is the ideal gas constant, which has a value of 8.314 J/mol·K, T is the temperature on the kelvin scale, Ea is the activation energy in J/mole, e is the constant 2.7183, and A is a constant called the frequency factor, which is related to the frequency of collisions and the orientation of the reacting molecules.
The Arrhenius equation can be used...
The Arrhenius equation can be used...
46.4K
Introduction to Mechanisms of Enzyme Catalysis
10.4K
For many years, scientists thought that enzyme-substrate binding took place in a simple "lock-and-key" fashion. This model stated that the enzyme and substrate fit together perfectly in one instantaneous step. However, current research supports a more refined view scientists call induced fit. The induced-fit model expands upon the lock-and-key model by describing a more dynamic interaction between enzyme and substrate. As the enzyme and substrate come together, their interaction causes...
10.4K
Overview of Nitrogen Metabolism
10.9K
Nitrogen is a very important element for life because it is a major constituent of proteins and nucleic acids. It is a macronutrient, and in nature, it is recycled from organic compounds and stored in the form of ammonia, ammonium ions, nitrate, nitrite, or nitrogen gas by many metabolic processes. Many of these metabolic processes are carried out only by prokaryotes.
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this...
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this...
10.9K
![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)