Cyclin-dependent kinase A (CDKA) is a key component for cell cycle progression. The catalytic kinase activity depends on the protein's ability to form an active complex with cyclins and on phosphoregulatory mechanisms. Cell cycle arrest and plant growth impairment under abiotic stress have been linked to different molecular processes triggered by increased levels of reactive oxygen and nitrogen species (ROS and RNS). Among these, posttranslational modifications (PTMs) of key proteins such as CDKA;1 may be of significance. Herein, isolated maize embryo axes were subjected to sodium nitroprusside (SNP) as an inductor of nitrosative conditions to evaluate if CDKA;1 protein was a target for RNS. A high degree of protein nitration was detected; this included the specific Tyr-nitration of CDKA;1. Tyr15 and Tyr19, located at the ATP-binding site, were the selective targets for nitration according to both in silico analysis using the predictive software GPS-YNO₂, and in vitro mass spectrometry studies of recombinant nitrated ZmCDKA;1. Spectrofluorometric measurements demonstrated a reduction of ZmCDKA;1-NO₂ affinity for ATP. From these results, we conclude that Tyr nitration in CDKA;1 could act as an active modulator of cell cycle progression during redox stress.

细胞周期蛋白依赖性激酶A（CDKA）是细胞周期进程的关键组成部分。催化激酶的活性取决于蛋白质与细胞周期蛋白形成活性复合物的能力以及磷酸调节机制。非生物胁迫下的细胞周期停滞和植物生长障碍与活性氧和氮种类（ROS和RNS）水平升高触发的不同分子过程有关。其中，关键蛋白（例如CDKA; 1）的翻译后修饰（PTM）可能很重要。在这里，分离的玉米胚轴经受亚硝普钠（SNP）作为亚硝化条件的诱导剂，以评估CDKA; 1蛋白是否是RNS的靶标。检测到高度的蛋白质硝化作用；这包括CDKA的特定Tyr硝化作用; 1。Tyr15和Tyr19位于ATP结合位点，使用预测软件GPS-YNO ₂进行计算机分析，以及重组硝化Zm CDKA的体外质谱研究； 1。荧光光谱法测量表明Zm CDKA; 1-NO ₂对ATP的亲和力降低。从这些结果，我们得出结论，CDKA; 1中的Tyr硝化可以在氧化还原应激期间充当细胞周期进程的主动调节剂。