Transmembrane kinases (TMKs) are members of the plant receptor‐like kinase (RLK) family. TMKs are characterized by an extracellular leucine‐rich‐repeat (LRR) domain, a single transmembrane region and a cytoplasmic kinase domain. TMKs have been shown to act as critical modulators of cell expansion and cell proliferation. Here, the crystal structure of the extracellular domain of TMK3 (TMK3‐ECD) was determined to a resolution of 2.06 Å, with an R_work of 17.69% and an R_free of 20.58%. Similar to the extracellular domain of TMK1, the TMK3‐ECD structure contains two solenoids with 13 LRRs and a non‐LRR region (316–364) between the tenth and 11th LRRs. A comparison of TMK3‐ECD with other LRR‐RLKs that contain a non‐LRR region indicates that the non‐LRR region plays a critical role in structural integrity and may contribute to ligand interactions. The non‐LRR region of TMK3‐ECD is characterized by two disulfide bonds that may have critical biological implications.

中文翻译：

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拟南芥受体样激酶 TMK3 胞外结构域的晶体结构。

跨膜激酶 (TMK) 是植物受体样激酶 (RLK) 家族的成员。TMK 的特点是具有胞外富含亮氨酸重复序列 (LRR) 结构域、单个跨膜区域和胞质激酶结构域。TMK 已被证明是细胞扩张和细胞增殖的关键调节剂。在这里，TMK3胞外结构域（TMK3-ECD）的晶体结构被确定为分辨率为2.06 Å，R功为_17.69 %，R_游离率为20.58%。与 TMK1 的胞外域类似，TMK3-ECD 结构包含两个具有 13 个 LRR 的螺线管以及第 10 个和第 11 个 LRR 之间的非 LRR 区域 (316-364)。TMK3-ECD 与其他包含非 LRR 区域的 LRR-RLK 的比较表明，非 LRR 区域在结构完整性中发挥着关键作用，并可能有助于配体相互作用。TMK3-ECD 的非 LRR 区域的特征是两个二硫键，这可能具有重要的生物学意义。