Mechanistic and Structural Studies of Novel Heme-Containing Peroxidases

新型含血红素过氧化物酶的机理和结构研究

• 批准号: 9604004
• 负责人: John Dawson
• 金额: $ 33.53万
• 依托单位: University of South Carolina at Columbia
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-02-01 至 2002-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9604004&HistoricalAwards=false
• 关键词: Mechanistic; Structural; Studies; Novel; Heme

9604004 Dawson Heme-containing peroxidases catalyze organic substrate oxidation with concomitant reduction of hydrogen peroxide to water. Two novel heme-containing peroxidases, one able to incorporate halogens into aromatic substrates and the other able to remove them, have recently been isolated from marine organisms and initially characterized. The properties of these enzymes challenge the current dogma of how peroxidases function: one chlorinates substrates without having a thiolate proximal ligand and the other both oxygenates and dehalogenates haloaromatics including the defluorination of fluoroaromatics. To better understand the unusual properties of these two heme peroxidases, spectroscopic, structural and mechanistic investigations will be carried out. These studies will involve the use of magnetic circular dichroism, EPR, and resonance Raman spectroscopy as well as high resolution crystallography to fully characterize the metal coordination structure and complete three dimensional structures of these two enzymes. Their mechanisms of action will be extensively examined including the use of isotopically labelled hydrogen peroxide to compare and contrast their mechanisms of hydrogen peroxide activation with those of the well studied plant peroxidases. Two novel enzymes from marine sources which are capable of generating and/or handling halogen-containing aromatic compounds have been isolated and will be thoroughly investigated including the determination of their mechanism of action and three dimensional structure. The first enzyme is able to incorporate halogens into aromatic substrates and may find applications as an industrial biocatalyst in the synthesis of halogen-containing aromatics. The second enzyme is able to remove halogens from aromatic compounds and is likely to have applications in bioremediation of water or soil contaminated with haloaromatics.

9604004 Dawson含血红素的过氧化物酶催化有机底物氧化，同时将过氧化氢还原为水。 两个新的血红素过氧化物酶，一个能够将卤素芳香族底物和其他能够去除它们，最近已被分离出海洋生物和初步的特点。 这些酶的性质挑战了目前过氧化物酶如何发挥作用的教条：一种在没有硫醇盐近端配体的情况下氯化底物，另一种既氧化又脱卤代芳族化合物，包括氟代芳族化合物的脱卤。 为了更好地了解这两个血红素过氧化物酶的不寻常的性质，光谱，结构和机制的调查将进行。 这些研究将涉及使用磁性圆二色性，EPR，共振拉曼光谱以及高分辨率晶体学，以充分表征金属配位结构和完整的三维结构，这两种酶。 他们的作用机制将被广泛研究，包括使用同位素标记的过氧化氢，比较和对比他们的过氧化氢活化机制与那些研究充分的植物过氧化物酶。 两种新的酶从海洋来源，能够产生和/或处理含卤素的芳香族化合物已被分离出来，并将进行彻底的研究，包括确定其作用机制和三维结构。 第一种酶能够将卤素结合到芳香族底物中，并且可以在含卤素芳香族化合物的合成中作为工业生物催化剂找到应用。 第二种酶能够从芳香族化合物中去除卤素，并且可能在被卤代芳香族化合物污染的水或土壤的生物修复中具有应用。