Structural basis of substrate recognition by the substrate binding protein (SBP) of a hydrazide transporter, obtained from Microbacterium hydrocarbonoxydans
Structural basis of substrate recognition by the substrate binding protein (SBP) of a hydrazide transporter, obtained from Microbacterium hydrocarbonoxydans
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酰肼转运蛋白的底物结合蛋白 (SBP) 识别底物的结构基础，从微杆菌烃氧化中获得
DOI：
10.1016/j.bbrc.2020.02.146
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Yajima S.
中科院分区：
文献类型：
--
作者：
Shimamura K;Akiyama T;Yokoyama K;Takenoya M;Ito S;Sasaki Y;Yajima S.
以酰肼类化合物为唯一碳源，分离到一株烃氧化微杆菌。代谢这些化合物的关键酶被鉴定为酰肼酶，并且通过基因组测序揭示了包含编码该酶的基因的操纵子。操纵子还含有编码ATP结合盒转运蛋白（ABC转运蛋白）的基因，预期该转运蛋白可转运酰肼化合物。底物结合蛋白（SBP）是转运蛋白的一个亚单位，在识别正确的转运底物方面起着重要作用。因此，为了阐明非天然酰肼化合物的识别机制，我们确定了SBP的晶体结构，从mM.烃氧化物（Mh-SBP），与酰肼化合物复合和不与酰肼化合物复合，分别在2.2 μ m和1.75 μ m分辨率。Mh-SBP的整体结构与寡肽转运体如OppA中的SBP相似。与之相比，Mh-SBP的配体和非配体结构呈现开-闭构象变化。有趣的是，该化合物与Mh-SBP的结合模式与该化合物与酰肼酶的结合模式几乎相同，这表明ABC转运蛋白用于转运这些化合物。此外，基于酰肼复合物的结构，对羟基苯甲酸酯，蛋白质的另一个推定的底物，成功地与Mh-SBP，得到对羟基苯甲酸酯复合物的结构。
Microbacteriumhydrocarbonoxydanswas isolated, using hydrazide compounds as its sole carbon source. The key enzyme that metabolizes these compounds was identified as hydrazidase, and the operon containing the gene coding for the enzyme, was revealed by genome sequencing. The operon also contained genes coding for an ATP-binding cassette transporter (ABC transporter), which was expected to transport the hydrazide compounds. Substrate binding protein (SBP), a component subunit of the transporter, plays an important role in recognizing the correct substrates for transport. Therefore, to elucidate the mechanism of recognition of the unnatural hydrazide compounds, we determined the crystal structures of the SBP, obtained fromM. hydrocarbonoxydans(Mh-SBP), complexed with and without the hydrazide compound, at 2.2 Å and 1.75 Å resolutions, respectively. The overall structures of Mh-SBP were similar to those of the SBP in oligopeptide transporters such as OppA. On comparison, the liganded and unliganded structures of Mh-SBP showed an open – close conformation change. Interestingly, the binding mode of the compound to Mh-SBP was almost identical to that of the compound to hydrazidase, suggesting that the ABC transporter served transporting these compounds. Furthermore, based on the hydrazide complex structure, paraben, the other putative substrate of the protein, was successfully used with Mh-SBP to obtain the paraben complex structure.