Atomic structures of the RNA end-healing 5′-OH kinase and 2′,3′-cyclic phosphodiesterase domains of fungal tRNA ligase: conformational switches in the kinase upon binding of the GTP phosphate donor
Atomic structures of the RNA end-healing 5′-OH kinase and 2′,3′-cyclic phosphodiesterase domains of fungal tRNA ligase: conformational switches in the kinase upon binding of the GTP phosphate donor
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DOI：
10.1093/nar/gkz1049
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发表时间：
2019-12-16
影响因子：
14.9
通讯作者：
Shuman, Stewart
中科院分区：
文献类型：
--
作者：
Banerjee, Ankan;Goldgur, Yehuda;Shuman, Stewart
真菌tRNA连接酶（Trl 1）通过2 '，3'-环状-PO 4和5 '-OH末端纠正RNA断裂。Trl 1由三个催化模块组成：N-末端连接酶（LIG）结构域;中央多核苷酸激酶（KIN）结构域;和C-末端环状磷酸二酯酶（CPD）结构域。在所有人类真菌病原体中发现的trl 1酶是抗真菌药物发现的未开发目标。在这里，我们报告了一个1.9埃的晶体结构的Trl 1 KIN-CPD的致病真菌白色念珠菌，它采用了扩展的构象，其中单独的KIN和CPD结构域连接的非结构化接头。CPD属于2 H磷酸转移酶超家族，由于其保守的中央凹β折叠及其双HxT基序组氨酸和苏氨酸与活性位点的磷酸相互作用。确定了2 H酶的真菌CPD进化枝中保守的另外的活性位点基序。我们目前的结构念珠菌Trl 1 KIN域在1.5至2.0埃的分辨率作为脱辅基酶和复合物与GTP中心点Mg 2+，IDP中心点PO 4，和dGDP中心点PO 4-突出的构象开关G-环（它识别鸟嘌呤碱基）和盖环（在核苷酸磷酸盐），伴随核苷酸结合。
Fungal tRNA ligase (Trl1) rectifies RNA breaks with 2',3'-cyclic-PO4 and 5'-OH termini. Trl1 consists of three catalytic modules: an N-terminal ligase (LIG) domain; a central polynucleotide kinase (KIN) domain; and a C-terminal cyclic phosphodiesterase (CPD) domain. Trl1 enzymes found in all human fungal pathogens are untapped targets for antifungal drug discovery. Here we report a 1.9 angstrom crystal structure of Trl1 KIN-CPD from the pathogenic fungus Candida albicans, which adopts an extended conformation in which separate KIN and CPD domains are connected by an unstructured linker. CPD belongs to the 2H phosphotransferase superfamily by dint of its conserved central concave beta sheet and interactions of its dual HxT motif histidines and threonines with phosphate in the active site. Additional active site motifs conserved among the fungal CPD clade of 2H enzymes are identified. We present structures of the Candida Trl1 KIN domain at 1.5 to 2.0 angstrom resolution-as apoenzyme and in complexes with GTP center dot Mg2+, IDP center dot PO4, and dGDP center dot PO4-that highlight conformational switches in the G-loop (which recognizes the guanine base) and lid-loop (poised over the nucleotide phosphates) that accompany nucleotide binding.