Analysis of the link between the redox state and enzymatic activity of the HtrA (DegP) protein from Escherichia coli.
Analysis of the link between the redox state and enzymatic activity of the HtrA (DegP) protein from Escherichia coli.
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DOI：
10.1371/journal.pone.0117413
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Skorko-Glonek J
中科院分区：
文献类型：
--
作者：
Koper T;Polit A;Sobiecka-Szkatula A;Wegrzyn K;Scire A;Figaj D;Kadzinski L;Zarzecka U;Zurawa-Janicka D;Banecki B;Lesner A;Tanfani F;Lipinska B;Skorko-Glonek J
细菌HtrA是一种在应激条件和致病过程中参与胞外活动的蛋白酶。一个原核模型HtrA(来自大肠杆菌的HtrA/DegP)需要激活才能有效地切割其底物。在酶的非活性状态下，其中一个被称为LA的调节环路在活性中心区域形成抑制接触。位于LA中间的二硫键的还原可在体内刺激htrA的活性，提示这种S-S键可能起到调节作用，尽管这种刺激的机制尚不清楚。在这里，我们证明了缺少S-S桥的htrA更有效地切割模型肽底物，并表现出对蛋白质底物更高的亲和力。缺少二硫化物的LA环更容易暴露在溶剂中；因此，至少涉及该环的一些相互作用肯定受到了干扰。没有S-S键的蛋白质表现出较低的热稳定性，更容易转化为十二聚体活性寡聚形式。因此，LA中缺乏二硫键影响了HtrA分子的稳定性和整体结构。在这项研究中，我们还证明了在体外，人硫氧还蛋白1能够还原HtrA，因此，HtrA的还原可以在酶的作用下进行。
Bacterial HtrAs are proteases engaged in extracytoplasmic activities during stressful conditions and pathogenesis. A model prokaryotic HtrA (HtrA/DegP from Escherichia coli) requires activation to cleave its substrates efficiently. In the inactive state of the enzyme, one of the regulatory loops, termed LA, forms inhibitory contacts in the area of the active center. Reduction of the disulfide bond located in the middle of LA stimulates HtrA activity in vivo suggesting that this S-S bond may play a regulatory role, although the mechanism of this stimulation is not known. Here, we show that HtrA lacking an S-S bridge cleaved a model peptide substrate more efficiently and exhibited a higher affinity for a protein substrate. An LA loop lacking the disulfide was more exposed to the solvent; hence, at least some of the interactions involving this loop must have been disturbed. The protein without S-S bonds demonstrated lower thermal stability and was more easily converted to a dodecameric active oligomeric form. Thus, the lack of the disulfide within LA affected the stability and the overall structure of the HtrA molecule. In this study, we have also demonstrated that in vitro human thioredoxin 1 is able to reduce HtrA; thus, reduction of HtrA can be performed enzymatically.
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DOI：
10.1016/j.bbamcr.2012.06.019
发表时间：
2012-10
影响因子：
5.1
作者：
Circu, Magdalena L.;Aw, Tak Yee
通讯作者：
Aw, Tak Yee
影响因子：
4.8
作者：
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通讯作者：
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DOI：
10.1073/pnas.1204791109
发表时间：
2012-05-08
影响因子：
11.1
作者：
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通讯作者：
Sauer, Robert T.
影响因子：
5.8
作者：
Larkin, M. A.;Blackshields, G.;Higgins, D. G.
通讯作者：
Higgins, D. G.
影响因子：
8
作者：
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