Enzymatic characterization of a class II lysyl-tRNA synthetase, LysS, from Myxococcus xanthus.
Enzymatic characterization of a class II lysyl-tRNA synthetase, LysS, from Myxococcus xanthus.
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DOI：
10.1016/j.abb.2015.05.014
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发表时间：
2015-08
影响因子：
3.9
通讯作者：
Manami Oka;K. Takegawa;Y. Kimura
中科院分区：
文献类型：
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作者：
Manami Oka;K. Takegawa;Y. Kimura
赖氨酰-tRNA合成酶在缺乏tRNA的情况下，能有效地从赖氨酰-AMP和三磷酸腺苷(ATP)合成二腺苷四磷酸(Ap4A)。我们鉴定了来自黄色粘球菌的重组II类赖氨酰-tRNA合成酶(Lyss)，发现它是单体，需要Mn2+来合成Ap4A。令人惊讶的是，在Mn2+存在的情况下，Zn2+对酶的活性有抑制作用。当Lyss与ATP、Mn2+、赖氨酸和无机焦磷酸酶孵育时，首先生成Ap4A和ADP，然后将Ap4A转化为二腺苷三磷酸(Ap3A)，最后将Ap3A转化为ADP。重组Lyss在不添加赖氨酸的情况下保持了Ap4A合成酶的活性。此外，当与Ap4A(负焦磷酸酶)孵育时，Lyss分别在有或没有赖氨酸的情况下转化Ap4A，主要是ATP和AMP，或ADP。这些结果证明了m。XanthusLysS具有不同于先前报道的II类赖氨酰-tRNA合成酶的酶学性质。
Lysyl-tRNA synthetases efficiently produce diadenosine tetraphosphate (Ap4A) from lysyl-AMP with ATP in the absence of tRNA. We characterized recombinant class II lysyl-tRNA synthetase (LysS) fromMyxococcus xanthusand found that it is monomeric and requires Mn2+for the synthesis of Ap4A. Surprisingly, Zn2+inhibited enzyme activity in the presence of Mn2+. When incubated with ATP, Mn2+, lysine, and inorganic pyrophosphatase, LysS first produced Ap4A and ADP, then converted Ap4A to diadenosine triphosphate (Ap3A), and finally converted Ap3A to ADP, the end product of the reaction. Recombinant LysS retained Ap4A synthase activity without lysine addition. Additionally, when incubated with Ap4A (minus pyrophosphatase), LysS converted Ap4A mainly ATP and AMP, or ADP in the presence or absence of lysine, respectively. These results demonstrate thatM. xanthusLysS has different enzymatic properties from class II lysyl-tRNA synthetases previously reported.