INVESTIGADORES
GERRARD WHEELER Mariel Claudia
congresos y reuniones científicas
Título:
Evidence of in vivo pyruvate carboxylase activity for an Arabidopsis NADP-malic enzyme
Autor/es:
BADIA, M. B.; MANS, R.; LIS, A.; TRONCONI, M. A.; ARIAS, C. L.; ANDREO, C. S.; DRINCOVICH, M. F.; VAN MARIS, A. J. A.; GERRARD WHEELER, M. C.
Lugar:
Rosario
Reunión:
Congreso; L Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología MolecularFisiología Vegetal; 2014
Institución organizadora:
Sociedad Argentina de Investigación en Bioquímica y Biología Molecular
Resumen:
NADP-malic enzyme (NADP-ME)
catalyzes the reversible oxidative decarboxylation of malate to pyruvate, CO2
and NADPH and is present as a multigene
family in A. thaliana. The reverse reaction
catalyzed by recombinant AtNADP-MEs was faster than reported for other animal
or plant isoforms. Particularly, AtNADP-ME2, the cytosolic isoform that mostly
contributes to the ME activity in all organs of the plant, presented the higher
catalytic efficiency of the family. In this work, AtNADP-ME2 as well as its
N-truncated version NADP-MEdel2 (unable to catalyze the carboxylation of pyruvate in vitro) were functionally
expressed in pyruvate carboxylase-negative (Pyc-) Saccharomyces
cerevisiae strains, which are incapable of growing on glucose as the sole
carbon source. Experiments conducted on agar plates as well as in batch
cultivation under ambient and thermodynamically favorable conditions showed that heterologous expression
of both NADP-ME2 and NADP-MEdel2 enabled growth of Pyc- S. cerevisiae on solely glucose. This capacity of rescuing Pyc- strains from C4
auxotrophy was dependent on the provision of the reaction substrates,
particularly CO2. These results indicate that AtNADP-ME2 is able to play an
anaplerotic role in vivo and provide
a basis for the study of the carboxylase activity of malic enzyme, which may
contribute to the synthesis of C4 compounds in plant cells.