Structural and functional characterization of MppR, an enduracididine biosynthetic enzyme from streptomyces hygroscopicus: functional diversity in the acetoacetate decarboxylase-like superfamily.
Structural and functional characterization of MppR, an enduracididine biosynthetic enzyme from streptomyces hygroscopicus: functional diversity in the acetoacetate decarboxylase-like superfamily.
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DOI：
10.1021/bi400397k
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发表时间：
2013-07-02
期刊：
影响因子：
2.9
通讯作者：
Silvaggi, Nicholas R.
中科院分区：
文献类型：
--
作者：
Burroughs, A. Maxwell;Hoppe, Robert W.;Goebel, Neal C.;Sayyed, Bilal H.;Voegtline, Tyler J.;Schwabacher, Alan W.;Zabriskie, T. Mark;Silvaggi, Nicholas R.
非蛋白氨基酸 enduracididine 是甘露肽霉素（一种环状糖肽抗生素）的关键成分，具有对抗耐药病原体（包括耐甲氧西林金黄色葡萄球菌）的活性。 Enduracididine 在吸水链霉菌中由三种酶 MppP、MppQ 和 MppR 产生。根据一级序列分析，MppP和Q是吡哆醛-5'-磷酸依赖性转氨酶； MppR 与乙酰乙酸脱羧酶具有较低但显着的序列同一性。每种酶催化的确切反应以及恩尿酸定途径中涉及的中间体目前尚不清楚。在此，我们介绍了 MppR 的生化和结构特征，证明了该酶的催化活性，并提供了有关其在恩尿酸苷生物合成中的作用的线索。生物信息学分析表明，MppR 属于乙酰乙酸脱羧酶样超家族 (ADCSF) 中以前未表征的家族，并表明 MppR 样酶可能催化与已充分表征的原型 ADCSF 脱羧酶活性不同的反应。 MppR 与乙酰乙酸脱羧酶具有高度的结构相似性，尽管各自的四级结构显着不同，并且活性位点的结构差异解释了观察到的脱羧酶活性的丧失。在丙酮酸和4-咪唑甲醛的混合物存在下MppR的晶体结构表明MppR催化这些化合物的羟醛缩合和随后的脱水。令人惊讶的是，在“4-羟基-2-酮精氨酸”和“2-酮恩尿酸定”的混合物存在下，MppR的结构仅显示与酶结合的“2-酮恩尿酸定”的正确4R-对映异构体。这些数据与 MppR 同源物的生物信息学分析一起，确定了乙酰乙酸脱羧酶样超家族中的一个新家族，该家族具有不同的活性位点结构，因此具有不同的生化功能。
The non-proteinogenic amino acid enduracididine is a critical component of the mannopeptimycins, cyclic glycopeptide antibiotics with activity against drug-resistant pathogens including methicillin-resistant Staphylococcus aureus. Enduracididine is produced in Streptomyces hygroscopicus by three enzymes, MppP, MppQ, and MppR. Based on primary sequence analysis, MppP and Q are pyridoxal-5'-phosphate-dependent aminotransferases; MppR shares low, but significant, sequence identity with acetoacetate decarboxylase. The exact reactions catalyzed by each enzyme, and the intermediates involved in the route to enduracididine are currently unknown. Herein we present biochemical and structural characterization of MppR that demonstrates a catalytic activity for this enzyme and provides clues about its role in enduracididine biosynthesis. Bioinformatic analysis shows that MppR belongs to a previously uncharacterized family within the acetoacetate decarboxylase-like superfamily (ADCSF) and suggests that MppR-like enzymes may catalyze reactions diverging from the well-characterized, prototypical ADCSF decarboxylase activity. MppR shares a high degree of structural similarity with acetoacetate decarboxylase, though the respective quaternary structures differ markedly and structural differences in the active site explain the observed loss of decarboxylase activity. The crystal structure of MppR in the presence of a mixture of pyruvate and 4-imidazolecarboxaldehyde shows that MppR catalyzes the aldol condensation of these compounds and subsequent dehydration. Surprisingly, the structure of MppR in the presence of a mixture of "4-hydroxy-2-ketoarginine" and "2-ketoenduracididine" shows only the correct 4R-enantiomer of "2-ketoenduracididine" bound to the enzyme. These data, together with bioinformatic analysis of MppR homologs, identifies a novel family within the acetoacetate decarboxylase-like superfamily with divergent active site structure and, consequently, biochemical function.
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DOI：
10.1107/s0907444905036693
发表时间：
2006-01-01
影响因子：
2.2
作者：
Evans, P
通讯作者：
Evans, P
影响因子：
2.9
作者：
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发表时间：
1997-04-01
期刊：
NATURE STRUCTURAL BIOLOGY
影响因子：
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通讯作者：
Wang, BC
DOI：
10.1107/s0907444910026582
发表时间：
2010-11-01
影响因子：
2.2
作者：
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通讯作者：
Adams, Paul D.