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oai:riuma.uma.es:10630/379202026-02-03T11:33:01Zcom_10630_2254col_10630_37953

00925njm 22002777a 4500 dc Llebrés, María Teresa author Pascual-Moreno, María Belén author Valle, Carolina author De-la-Torre-Fazio, Fernando Nicolás author Valderrama-Martín, José Miguel author Gómez, Luis author Ávila-Sáez, Concepción author Cánovas-Ramos, Francisco Miguel author 2020 High levels of nitrogen are stored as arginine during the last stages of seed formation in maritime pine (Pinus pinaster Aiton). The protein sensor PII regulates the feedback inhibition of arginine biosynthesis through interaction with the key enzyme N-acetylglutamate kinase (NAGK). In this study, the structural and functional characteristics of PII have been investigated in maritime pine to get insights into the regulation of arginine metabolism. Two different forms of PII have been identified, PpPIIa and PpPIIb, which differ in their amino acid sequence and most likely correspond to splicing variants of a single gene in the pine genome. Two PII variants are also present in other pine species but not in other conifers such as spruces. PpPIIa and PpPIIb are trimeric proteins for which structural modeling predicts similar tridimensional protein core structures. Both are located in the chloroplast, where the PII-target enzyme PpNAGK is also found. PpPIIa, PpPIIb, and PpNAGK have been recombinantly produced to investigate the formation of NAGK-PII complexes. The interaction of PpPIIa/PpPIIb and PpNAGK may be enhanced by glutamine and contribute to relieve the feedback inhibition of PpNAGK by arginine. Expression analysis of PpPII genes revealed that PpIIa transcripts were predominant during embryogenesis and germination. The potential roles of PpPIIa and PpPIIb in the regulation of arginine metabolism of maritime pine are discussed. Llebrés MT, Pascual MB, Valle C, de la Torre FN, Valderrama-Martin JM, Gómez L, Avila C and Cánovas FM (2020) Structural and Functional Characteristics of Two Molecular Variants of the Nitrogen Sensor PII in Maritime Pine. Front. Plant Sci. 11:823. doi: 10.3389/fpls.2020.00823 1664-462X https://hdl.handle.net/10630/37920 10.3389/fpls.2020.00823 Plantas - Efectos del nitrógeno Pinos - Metabolismo Structural and functional characteristics of two molecular variants of the nitrogen sensor PII in maritime pine.