A novel C-domain-dependent inhibition of the rainbow trout CMP-sialic acid synthetase activity by CMP-deaminoneuraminic acid
A novel C-domain-dependent inhibition of the rainbow trout CMP-sialic acid synthetase activity by CMP-deaminoneuraminic acid
复制标题
CMP-脱氨基神经氨酸对虹鳟鱼 CMP-唾液酸合成酶活性的新型 C 结构域依赖性抑制
DOI：
10.1016/j.bbrc.2022.05.031
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发表时间：
2022
影响因子：
3.1
通讯作者：
Kitajima Ken
中科院分区：
文献类型：
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作者：
Wu Di;Gilormini Pierre-Andr?;Toda Sakura;Biot Christophe;Lion C?dric;Gu?rardel Yann;Sato Chihiro;Kitajima Ken
CMP-唾液酸合成酶（CSS）使用CTP将游离唾液酸（Sia）活化为CMP-Sia，并且是细胞表面糖缀合物唾液酸化的先决条件。脊椎动物CSS由两个结构域组成，催化N结构域和非催化C结构域。虽然C-结构域不是CSS酶合成CMP-Sia所必需的，但其参与催化活性仍然未知。首先，利用31 P NMR对CSS催化反应进行实时监测。虽然缺乏C结构域的rtCSS（rtCSS-N）类似地激活脱氨基神经氨酸（Kdn）和N-乙酰神经氨酸（Neu 5Ac），但全长rtCSS（rtCSS-FL）不像Neu 5Ac那样有效地激活Kdn。这些结果表明，C-结构域的rtCSS影响酶的活性，当Kdn用作底物。其次，在不同浓度的CMP-Kdn下测量rtCSS-FL和rtCSS-N的酶活性。CMP-Kdn仅对rtCSS-FL观察到抑制作用，但对rtCSS-N未观察到抑制作用，表明抑制作用是C结构域依赖性的。第三，还使用小鼠CSS（mCSS）研究了CMP-Kdn的抑制作用。然而，即使在高浓度的CMP-Kdn下，mCSS也没有观察到抑制。综上所述，数据表明C结构域参与了rtCSS的CMP-Kdn依赖性抑制，这是虹鳟鱼中Sia代谢的新调节。
The CMP-sialic acid synthetase (CSS) activates free sialic acid (Sia) to CMP-Sia using CTP, and is prerequisite for the sialylation of cell surface glycoconjugates. The vertebrate CSS consists of two domains, a catalytic N-domain and a non-catalytic C-domain. Although the C-domain is not required for the CSS enzyme to synthesize CMP-Sia, its involvement in the catalytic activity remains unknown. First, the real-time monitoring of CSS-catalyzed reaction was performed by31P NMR using the rainbow trout CSS (rtCSS). While a rtCSS lacking the C-domain (rtCSS-N) similarly activated both deaminoneuraminic acid (Kdn) andN-acetylneuraminic acid (Neu5Ac), the full-length rtCSS (rtCSS-FL) did not activate Kdn as efficiently as Neu5Ac. These results suggest that the C-domain of rtCSS affects the enzymatic activity, when Kdn was used as a substrate. Second, the enzymatic activity of rtCSS-FL and rtCSS-N was measured under various concentrations of CMP-Kdn. Inhibition by CMP-Kdn was observed only for rtCSS-FL, but not for rtCSS-N, suggesting that the inhibition was C-domain-dependent. Third, the inhibitory effect of CMP-Kdn was also investigated using the mouse CSS (mCSS). However, no inhibition was observed with mCSS even at high concentrations of CMP-Kdn. Taken together, the data demonstrated that the C-domain is involved in the CMP-Kdn-dependent inhibition of rtCSS, which is a novel regulation of the Sia metabolism in rainbow trout.