Structural basis of the binding affinity of chemoreceptors Mlp24p and Mlp37p for various amino acids
Structural basis of the binding affinity of chemoreceptors Mlp24p and Mlp37p for various amino acids
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化学感受器Mlp24p和Mlp37p对各种氨基酸的结合亲和力的结构基础
DOI：
10.1016/j.bbrc.2019.12.055
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发表时间：
2020
影响因子：
3.1
通讯作者：
Imada Katsumi
中科院分区：
文献类型：
--
作者：
Takahashi Yohei;Nishiyama So-ichiro;Kawagishi Ikuro;Imada Katsumi
环境感知对细菌的生存和致病性至关重要。细菌通过化学受体蛋白感知环境化学物质，例如甲基接受趋化蛋白(MCP)。霍乱弧菌是霍乱的病原体，至少有44种化学受体蛋白与MCP样蛋白(MLP)同源。Mlp24和Mlp37是dCACHE型化学感受器，可感受多种氨基酸。Mlp24对霍乱毒素的产生很重要，而Mlp37与生物膜的形成有关。Mlp24和Mlp37的周质配体结合区(分别为Mlp24p和Mlp37p)具有相似的氨基酸序列、三级和四级结构，以及配体氨基酸骨架识别的共同机制。然而，Mlp37p对多种氨基酸和牛磺酸具有相似的亲和力，而Mlp24p对各种氨基酸表现出不同的亲和力，不与牛磺酸结合。在这里，我们求解了L-精氨酸配合物Mlp37P的晶体结构，并与以前确定的Mlp37P、Mlp24P及其配体配合物的结构进行了比较。我们发现，Mlp37p根据配体的大小和形状改变形成配体结合口袋上壁的环的构象，从而对不同的配体表现出相似的亲和力。
Environmental sensing is crucial for bacterial survival and pathogenicity. Bacteria sense environmental chemicals using chemoreceptor proteins, such as Methyl-accepting Chemotaxis Proteins (MCPs).Vibrio cholerae, the etiological agent of cholera, has at least 44 chemoreceptor proteins homologous to MCP-Like Proteins (MLPs). Mlp24 and Mlp37 are dCACHE type chemoreceptors that senses various amino acids. Mlp24 is important for cholera toxin production, whereas Mlp37 is related to biofilm formation. The periplasmic ligand binding regions of Mlp24 and Mlp37 (Mlp24p and Mlp37p, respectively) share similar amino acid sequences, tertiary and quaternary structures, and a common mechanism for the ligand amino acid backbone recognition. However, Mlp37p recognizes variousl-amino acids and taurine with similar affinity whereas Mlp24p shows different binding affinities for variousl-amino acids and does not bind taurine. Here we solved the crystal structure of Mlp37p in complex withl-arginine and compared it with previously determined structures of Mlp37p, Mlp24p and their ligand complexes. We found that Mlp37p changes the conformation of the loop that forms the upper wall of the ligand binding pocket according to size and shape of the ligand, and thereby show similar affinity for various ligands.