Specific Arabidopsis thaliana malic enzyme isoforms can provide anaplerotic pyruvate carboxylation function in Saccharomyces cerevisiae
2017 (English)In: The FEBS Journal, ISSN 1742-464X, E-ISSN 1742-4658, Vol. 284, no 4, 654-665 p.Article in journal (Refereed) Published
NAD(P)-malic enzyme (NAD(P)-ME) catalyzes the reversible oxidative decarboxylation of malate to pyruvate, CO2, and NAD(P)H and is present as a multigene family in Arabidopsis thaliana. The carboxylation reaction catalyzed by purified recombinant Arabidopsis NADP-ME proteins is faster than those reported for other animal or plant isoforms. In contrast, no carboxylation activity could be detected in vitro for the NAD-dependent counterparts. In order to further investigate their putative carboxylating role in vivo, Arabidopsis NAD(P)-ME isoforms, as well as the NADP-ME2del2 (with a decreased ability to carboxylate pyruvate) and NADP-ME2R115A (lacking fumarate activation) versions, were functionally expressed in the cytosol of pyruvate carboxylase-negative (Pyc(-)) Saccharomyces cerevisiae strains. The heterologous expression of NADP-ME1, NADP-ME2 (and its mutant proteins), and NADP-ME3 restored the growth of Pyc(-) S. cerevisiae on glucose, and this capacity was dependent on the availability of CO2. On the other hand, NADP-ME4, NAD-ME1, and NAD-ME2 could not rescue the Pyc(-) strains from C-4 auxotrophy. NADP-ME carboxylation activity could be measured in leaf crude extracts of knockout and over-expressing Arabidopsis lines with modified levels of NADP-ME, where this activity was correlated with the amount of NADP-ME2 transcript. These results indicate that specific A. thaliana NADP-ME isoforms are able to play an anaplerotic role in vivo and provide a basis for the study on the carboxylating activity of NADP-ME, which may contribute to the synthesis of C-4 compounds and redox shuttling in plant cells.
Place, publisher, year, edition, pages
WILEY , 2017. Vol. 284, no 4, 654-665 p.
anaplerotic role, C-4 organic acids, malate synthesis, plant metabolism, Saccharomyces cerevisiae
IdentifiersURN: urn:nbn:se:kth:diva-205137DOI: 10.1111/febs.14013ISI: 000396944900011PubMedID: 28075062ScopusID: 2-s2.0-85011286357OAI: oai:DiVA.org:kth-205137DiVA: diva2:1088481
QC 201704122017-04-122017-04-122017-04-12Bibliographically approved