Light-driven DNA修复酶催化:回顾一下最近的生物物理研究光裂合酶。
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Light-driven DNA修复酶催化:回顾一下最近的生物物理研究光裂合酶。
Biochim Biophys学报。2005年2月25日,1707 (1):1。
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15721603 (在PubMed]
- 文摘
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50多年前,在酶的初步实验photorepair的紫外线(UV)受损的DNA报告[Proc。国家的。学会科学。美国35 (1949)73)。这一发现后不久,认识到一个酶,光裂合酶,能够修复UV-induced DNA损伤的有效使用蓝光扭转它们的形成。酶的过程叫做DNA光致复活作用取决于非共价结合代数余子式,黄素腺嘌呤二核苷酸(时尚)。黄素随处可见redox-active催化剂在一,两电子转移反应的许多生物学过程。然而,在光裂合酶的情况下,不仅极化子时尚代数余子式的氧化还原性质剥削,同时,或许更重要的是,其激发态性质。在催化地活跃,充分降低氧化还原形式,时尚在蓝色和近紫外线吸收可见光的范围。虽然没有直接的实验证据,似乎从激发单重态的普遍接受,两个主要的发色团发起一个还原乳沟DNA photodamages环丁烷嘧啶二聚体和(6 - 4)photoproducts短途电子转移的DNA损伤。 Back electron transfer from the repaired DNA segment is believed to eventually restore the initial redox states of the cofactor and the DNA nucleobases, resulting in an overall reaction with net-zero exchanged electrons. Thus, the entire process represents a true catalytic cycle. Many biochemical and biophysical studies have been carried out to unravel the fundamentals of this unique mode of action. The work has culminated in the elucidation of the three-dimensional structure of the enzyme in 1995 that revealed remarkable details, such as the FAD-cofactor arrangement in an unusual U-shaped configuration. With the crystal structure of the enzyme at hand, research on photolyases did not come to an end but, for good reason, intensified: the geometrical structure of the enzyme alone is not sufficient to fully understand the enzyme's action on UV-damaged DNA. Much effort has therefore been invested to learn more about, for example, the geometry of the enzyme-substrate complex, and the mechanism and pathways of intra-enzyme and enzyme <-->DNA electron transfer. Many of the key results from biochemical and molecular biology characterizations of the enzyme or the enzyme-substrate complex have been summarized in a number of reviews. Complementary to these articles, this review focuses on recent biophysical studies of photoreactivation comprising work performed from the early 1990s until the present.