T273 plays an important role in the activity and structural stability of arginine kinase.
T273 plays an important role in the activity and structural stability of arginine kinase.
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DOI：
10.1016/j.ijbiomac.2013.10.019
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发表时间：
2014-02
影响因子：
8.2
通讯作者：
Qing-yun Wu;Hua-Yan Guo;Hong-Li Geng;B. Ru;Jiang Cao;Chong Chen;L. Zeng;Xiao-yun Wang;Feng Li;K. Xu
中科院分区：
文献类型：
--
作者：
Qing-yun Wu;Hua-Yan Guo;Hong-Li Geng;B. Ru;Jiang Cao;Chong Chen;L. Zeng;Xiao-yun Wang;Feng Li;K. Xu
精氨酸激酶（AK）是无脊椎动物细胞能量代谢的关键酶，催化磷酸精氨酸到ADP的可逆磷酰转移。氨基酸残基C271参与保持AK的活性并限制底物精氨酸的取向。然而，C271相互作用氨基酸残基在AK的底物协同作用、活性和结构稳定性中的作用仍不清楚。晶体结构分析表明，氨基酸残基T273与C271相互作用，可能对维持AK的活性、底物协同作用和结构稳定性起重要作用。突变T273G和T273A导致酶活性明显丧失，底物协同作用和结构稳定性明显降低。此外，光谱实验表明，突变T273G和T273A损害AK的结构，并导致他们的部分未折叠状态。不能折叠到功能状态使得突变在环境压力下易于聚集。此外，突变T273S和T273D对AK的活性和结构稳定性几乎没有影响。本研究表明，T273残基在AK的活性、底物协同作用和结构稳定性中起关键作用。
Arginine kinase (AK) is a key enzyme for cellular energy metabolism, catalyzing the reversible phosphoryl transfer from phosphoarginine to ADP in invertebrates. The amino acid residue C271 is involved in keeping AK's activity and constraining the orientation of the substrate arginine. However, the roles of the C271 interaction amino acid residues in AK's substrate synergism, activity and structural stability are still unclear. The crystal structure of AK implied that the amino acid residue T273 interacted with the residue C271 and might play vital roles in keeping AK's activity, substrate synergism and structural stability. The mutations T273G and T273A led to significantly loss of activity, obviously decreased of substrate synergism and structural stability. Furthermore, spectroscopic experiments indicated that mutations T273G and T273A impaired the structure of AK and led them to a partially unfolded state. The inability to fold to the functional state made the mutations prone to aggregate under environmental stresses. Moreover, the mutations T273S and T273D almost had no effects on AK's activity and structural stability. This study herein indicated that the residue T273 played key roles in AK's activity, substrate synergism and structural stability.