Tyr-nitration in maize CDKA;1 results in lower affinity for ATP binding

CABRERA A; MENDEZ AEA; BENAVIDES MP; MANGIALAVORI I; GALLEGO SM

BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2020 vol. 1868

1570-9639

Cyclin-dependent kinase A (CDKA) is a key component for cell cycle progression. The catalytic kinase activitydepends 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 molecularprocesses 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, isolatedmaize embryo axes were subjected to sodium nitroprusside (SNP) as an inductor of nitrosative conditions toevaluate if CDKA;1 protein was a target for RNS. A high degree of protein nitration was detected; this includedthe specific Tyr-nitration of CDKA;1. Tyr15 and Tyr19, located at the ATP-binding site, were the selective targetsfor nitration according to both in silico analysis using the predictive software GPS-YNO2, and in vitro massspectrometry studies of recombinant nitrated ZmCDKA;1. Spectrofluorometric measurements demonstrated areduction of ZmCDKA;1-NO2 affinity for ATP. From these results, we conclude that Tyr nitration in CDKA;1 couldact as an active modulator of cell cycle progression during redox stress.