Bridging the functional gap between reactivity and inhibition in dehaloperoxidase B from Amphitrite ornata: Mechanistic and structural studies with 2,4- and 2,6-dihalophenols
Bridging the functional gap between reactivity and inhibition in dehaloperoxidase B from Amphitrite ornata: Mechanistic and structural studies with 2,4- and 2,6-dihalophenols
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弥合 Amphitrite ornata 脱卤过氧化物酶 B 的反应性和抑制性之间的功能差距：2,4- 和 2,6-二卤代酚的机理和结构研究
DOI：
10.1016/j.jinorgbio.2022.111944
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发表时间：
2022
影响因子：
3.9
通讯作者：
Ghiladi, Reza A.
中科院分区：
文献类型：
--
作者：
Malewschik, Talita;Carey, Leiah M.;de Serrano, Vesna;Ghiladi, Reza A.
从海洋蠕虫中提取的多功能催化珠蛋白脱卤过氧化物酶（DHP）被证明可以催化2,4-和2,6-二卤酚（DXP; X = F, Cl, Br）的h2o2依赖性氧化。通过LC-MS对产物进行鉴定，发现了多种不同程度氧化和/或脱卤的单体产物，以及n ~ 6的低聚物。机械和18o标记研究表明，通过过氧化物酶和过氧酶活性，二卤酚的顺序氧化。结合研究证实2,4- dxp （X = Cl, Br）在所有已知的DHP底物中具有最高的亲和力。x射线晶体学鉴定了2,4-和2,6- dxp底物在DHP疏水远端口袋中的不同结合位置。卤素数量与底物结合方向之间的相关性揭示了单-（4-卤代酚）、二-（2,4-和2,6-二卤代酚）和三卤代酚（2,4,6-三卤代酚）的卤素依赖结合基序。综上所述，二卤酚与DHP反应性的研究结果促进了我们对这些化合物如何分别桥接它们的单卤酚和三卤酚对应物的抑制和氧化功能的理解，并进一步深入了解与多功能催化珠蛋白相关的蛋白质结构-功能范式，与它们的单功能类似物相比。
The multifunctional catalytic globin dehaloperoxidase (DHP) from the marine wormAmphitrite ornatawas shown to catalyze the H2O2-dependent oxidation of 2,4- and 2,6-dihalophenols (DXP; X = F, Cl, Br). Product identification by LC-MS revealed multiple monomeric products with varying degrees of oxidation and/or dehalogenation, as well as oligomers with n up to 6. Mechanistic and18O-labeling studies demonstrated sequential dihalophenol oxidation via peroxidase and peroxygenase activities. Binding studies established that 2,4-DXP (X = Cl, Br) have the highest affinities of any known DHP substrate. X-ray crystallography identified different binding positions for 2,4- and 2,6-DXP substrates in the hydrophobic distal pocket of DHP. Correlation between the number of halogens and the substrate binding orientation revealed a halogen-dependent binding motif for mono- (4-halophenol), di- (2,4- and 2,6-dihalophenol) and trihalophenols (2,4,6-trihalopenol). Taken together, the findings here on dihalophenol reactivity with DHP advance our understanding of how these compounds bridge the inhibitory and oxidative functions of their mono- and trihalophenol counterparts, respectively, and provide further insight into the protein structure-function paradigm relevant to multifunctional catalytic globins in comparison to their monofunctional analogs.