Substrate-Triggered μ-Peroxodiiron(III) Intermediate in the 4-Chloro-l-Lysine-Fragmenting Heme-Oxygenase-like Diiron Oxidase (HDO) BesC: Substrate Dissociation from, and C4 Targeting by, the Intermediate.
Substrate-Triggered μ-Peroxodiiron(III) Intermediate in the 4-Chloro-l-Lysine-Fragmenting Heme-Oxygenase-like Diiron Oxidase (HDO) BesC: Substrate Dissociation from, and C4 Targeting by, the Intermediate.
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DOI：
10.1021/acs.biochem.1c00774
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发表时间：
2022-04-19
期刊：
影响因子：
2.9
通讯作者：
Bollinger JM Jr
中科院分区：
文献类型：
--
作者：
McBride MJ;Nair MA;Sil D;Slater JW;Neugebauer ME;Chang MCY;Boal AK;Krebs C;Bollinger JM Jr
来自链霉菌（Streptomyces cattleya）中的β-乙炔基-L-丝氨酸生物合成途径的酶BesC将4-氯-L-赖氨酸（由BesD从L-赖氨酸产生）片段化为氨、甲醛和4-氯-L-烯丙基甘氨酸，并且可以类似地将L-Lys本身片段化。BesC属于新兴的具有“血红素加氧酶样”蛋白折叠（HDO）的O2活化非血红素二铁酶家族。在这里，我们表明，L-Lys或类似物的结合触发捕获O2的蛋白质的二铁（II）辅因子，形成一个蓝色的μ-过氧二铁（III）的中间体类似于以前的特点，在其他两个HDO，烯烃安装脂肪酸脱羧酶，UndA，和胍基-N-加氧酶结构域的SznF。与4-硫代-L-赖氨酸和（4 RS）-氯-DL-赖氨酸反应中中间体的衰变比与L-赖氨酸本身反应快约5倍和约30倍，以及与4，4，5，5-[2 H]-L-赖氨酸反应中中间体衰变和L-烯丙基甘氨酸生成的初级氘动力学同位素效应（D-KIE），表明过氧化物中间体或可逆连接的后继络合物从C4中提取氢原子以使得能够形成烯烃。令人惊讶的是，缓慢的底物L-Lys可以在触发中间体形成后解离，从而允许更好的底物之一结合和反应。载脂蛋白BesC的结构和Fe（II）与底物结合之间的联系表明，触发事件涉及条件稳定HDO核心的配体提供螺旋3（α3）的诱导有序化。正如之前对SznF所提出的，动态α3也可能在过氧化物中间体衰变后引发二铁（III）产物簇的自发降解，这是新生HDO家族的特征。
The enzyme BesC from the β-ethynyl-L-serine biosynthetic pathway in Streptomyces cattleya fragments 4-chloro-L-lysine (produced from L-Lysine by BesD) to ammonia, formaldehyde, and 4-chloro-L-allylglycine and can analogously fragment L-Lys itself. BesC belongs to the emerging family of O2-activating non-heme-diiron enzymes with the “heme-oxygenase-like” protein fold (HDOs). Here we show that binding of L-Lys or an analog triggers capture of O2 by the protein’s diiron(II) cofactor to form a blue μ-peroxodiiron(III) intermediate analogous to those previously characterized in two other HDOs, the olefin-installing fatty acid decarboxylase, UndA, and the guanidino-N-oxygenase domain of SznF. The ~ 5- and ~ 30-fold faster decay of the intermediate in reactions with 4-thia-L-Lys and (4RS)-chloro-DL-lysine than in the reaction with L-Lys itself, and the primary deuterium kinetic isotope effects (D-KIEs) on decay of the intermediate and production of L-allylglycine in the reaction with 4,4,5,5-[2H]-L-Lys, suggest that the peroxide intermediate or a reversibly connected successor complex abstracts a hydrogen atom from C4 to enable olefin formation. Surprisingly, the sluggish substrate L-Lys can dissociate after triggering the intermediate to form, thereby allowing one of the better substrates to bind and react. The structure of apo BesC and the demonstrated linkage between Fe(II) and substrate binding suggest that the triggering event involves an induced ordering of ligand-providing helix 3 (α3) of the conditionally stable HDO core. As previously suggested for SznF, the dynamic α3 also likely initiates the spontaneous degradation of the diiron(III) product cluster after decay of the peroxide intermediate, a trait emerging as characteristic of the nascent HDO family.
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影响因子：
15
作者：
Korboukh, Victoria Korneeva;Li, Ning;Barr, Eric W.;Bollinger, J. Martin, Jr.;Krebs, Carsten
通讯作者：
Krebs, Carsten
影响因子：
15
作者：
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Lippard, SJ
影响因子：
15
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Kim, K;Lippard, SJ
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影响因子：
15
作者：
He, Hai-Yan;Henderson, Alyssa C.;Ryan, Katherine S.
通讯作者：
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影响因子：
62.1
作者：
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通讯作者：
Que L Jr