RT Journal Article
T1 Pine has two glutamine synthetase paralogs, GS1b.1 and GS1b.2, exhibiting distinct biochemical properties
A1 Valderrama-Martín, José Miguel
A1 Ortigosa Peña, Francisco
A1 Aledo-Ramos, Juan Carlos
A1 Ávila-Sáez, Concepción
A1 Cánovas-Ramos, Francisco Miguel
A1 Cañas-Pendón, Rafael Antonio
K1 Bioquímica
K1 Glutamina
K1 Metabolismo
AB The enzyme glutamine synthetase (EC 6.3.1.2) is mainly responsible for the incorporation of inorganic nitrogen into organic molecules in plants. In the present work, a pine (Pinus pinaster) GS1 (PpGS1b.2) gene wasidentified, showing a high sequence identity with the GS1b.1 gene previously characterized in conifers. Phylogenetic analysis revealed that the presence of PpGS1b.2 is restricted to the genera Pinus and Picea and isnot found in other conifers. Gene expression data suggest a putative role of PpGS1b.2 in plant development, similar to other GS1b genes from angiosperms, suggesting evolutionary convergence. The characterization of GS1b.1 and GS1b.2 at the structural, physicochemical, and kinetic levels has shown differenceseven though they have high sequence homology. GS1b.2 had a lower optimum pH (6 vs. 6.5) and was lessthermally stable than GS1b.1. GS1b.2 exhibited positive cooperativity for glutamate and substrate inhibitionfor ammonium. However, GS1b.1 exhibited substrate inhibition behavior for glutamate and ATP. Alterationsin the kinetic characteristics produced by site-directed mutagenesis carried out in this work strongly suggest an implication of amino acids at positions 264 and 267 in the active center of pine GS1b.1 and GS1b.2being involved in affinity toward ammonium. Therefore, the amino acid differences between GS1b.1 andGS1b.2 would support the functioning of both enzymes to meet distinct plant needs
PB Wiley
YR 2023
FD 2023
LK https://hdl.handle.net/10630/26341
UL https://hdl.handle.net/10630/26341
LA eng
NO Valderrama‐Martín, Ortigosa, F., Aledo, J. C., Ávila, C., Cánovas, F. M., & Cañas, R. A. (2023). Pine has two glutamine synthetase paralogs, GS1b.1 and GS1b.2, exhibiting distinct biochemical properties. The Plant Journal : for Cell and Molecular Biology, 113(6), 1330–1347. https://doi.org/10.1111/tpj.16113
NO Funding for open access charge: Universidad de Malaga/CBUA.
DS RIUMA. Repositorio Institucional de la Universidad de Málaga
RD 12 abr 2026