Structural and Biochemical Characterization of the Francisella tularensis Pathogenicity Regulator, Macrophage Locus Protein A (MglA).
Structural and Biochemical Characterization of the Francisella tularensis Pathogenicity Regulator, Macrophage Locus Protein A (MglA).
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DOI：
10.1371/journal.pone.0128225
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Schumacher MA
中科院分区：
文献类型：
--
作者：
Cuthbert BJ;Brennan RG;Schumacher MA
土拉弗朗西斯菌是已知最具传染性的细菌之一，也是土拉菌病的病原体。弗朗西斯菌的毒力源自 33 kilobase (Kb) 的致病性岛 (FPI)，该岛由巨噬细胞基因座蛋白 A (MglA) 和严格饥饿蛋白 A (SspA) 调节。这些蛋白质与 RNA 聚合酶 (RNAP) 和致病性岛基因调节因子 (PigR) 相互作用，激活 FPI 转录。然而，所涉及的分子机制尚不清楚。事实上，虽然大多数细菌 SspA 蛋白作为同二聚体来激活转录，但土拉杆菌 SspA 与 MglA 蛋白形成异二聚体，这是土拉杆菌所特有的。为了深入了解 MglA 功能，我们进行了结构和生化研究。 MglA 结构表明它包含与 SspA 蛋白家族相似的折叠。出乎意料的是，MglA也在晶体中形成了同型二聚体。化学交联和尺寸排阻色谱 (SEC) 研究表明，MglA 能够在溶液中自缔合形成二聚体，但它优先与 SspA 异二聚化。最后，MglA 结构揭示了用于结晶的苹果酸结合在二聚体形成的开放口袋中，这表明该裂缝可能在小分子配体结合中发挥作用。该结合区域相对于最近绘制的PigR和RNAP相互作用位点的位置表明小分子结合在MglA和SspA·MglA功能中的可能作用。
Francisella tularensis is one of the most infectious bacteria known and is the etiologic agent of tularemia. Francisella virulence arises from a 33 kilobase (Kb) pathogenicity island (FPI) that is regulated by the macrophage locus protein A (MglA) and the stringent starvation protein A (SspA). These proteins interact with both RNA polymerase (RNAP) and the pathogenicity island gene regulator (PigR) to activate FPI transcription. However, the molecular mechanisms involved are not well understood. Indeed, while most bacterial SspA proteins function as homodimers to activate transcription, F. tularensis SspA forms a heterodimer with the MglA protein, which is unique to F. tularensis. To gain insight into MglA function, we performed structural and biochemical studies. The MglA structure revealed that it contains a fold similar to the SspA protein family. Unexpectedly, MglA also formed a homodimer in the crystal. Chemical crosslinking and size exclusion chromatography (SEC) studies showed that MglA is able to self-associate in solution to form a dimer but that it preferentially heterodimerizes with SspA. Finally, the MglA structure revealed malate, which was used in crystallization, bound in an open pocket formed by the dimer, suggesting the possibility that this cleft could function in small molecule ligand binding. The location of this binding region relative to recently mapped PigR and RNAP interacting sites suggest possible roles for small molecule binding in MglA and SspA•MglA function.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
3.2
作者：
Ludu, Jagjit S.;de Bruin, Olle M.;Nano, Francis E.
通讯作者：
Nano, Francis E.
DOI：
10.1107/s0907444909052925
发表时间：
2010-02
期刊：
Acta crystallographica. Section D, Biological crystallography
影响因子：
--
作者：
Adams PD;Afonine PV;Bunkóczi G;Chen VB;Davis IW;Echols N;Headd JJ;Hung LW;Kapral GJ;Grosse-Kunstleve RW;McCoy AJ;Moriarty NW;Oeffner R;Read RJ;Richardson DC;Richardson JS;Terwilliger TC;Zwart PH
通讯作者：
Zwart PH
影响因子：
6.7
作者：
Charity JC;Blalock LT;Costante-Hamm MM;Kasper DL;Dove SL
通讯作者：
Dove SL
影响因子：
5.2
作者：
Bröms JE;Sjöstedt A;Lavander M
通讯作者：
Lavander M