Pyrroline-5-carboxylate metabolism protein complex detected in Arabidopsis thaliana leaf mitochondria

verfasst von

Yao Zheng, Cécile Cabassa-Hourton, Holger Eubel, Guillaume Chevreux, Laurent Lignieres, Emilie Crilat, Hans-Peter Braun, Sandrine Lebreton, Arnould Savouré

Abstract

Proline dehydrogenase (ProDH) and pyrroline-5-carboxylate (P5C) dehydrogenase (P5CDH) catalyze the oxidation of proline into glutamate via the intermediates P5C and glutamate-semialdehyde (GSA), which spontaneously interconvert. P5C and GSA are also intermediates in the production of glutamate from ornithine and α-ketoglutarate catalyzed by ornithine δ-aminotransferase (OAT). ProDH and P5CDH form a fused bifunctional PutA enzyme in Gram-negative bacteria and are associated in a bifunctional substrate channelling complex in Thermus thermophilus, but the physical proximity of ProDH and P5CDH in eukaryotes has not been described. Here we report evidence of physical proximity and interactions between Arabidopsis ProDH, P5CDH and OAT in the mitochondria of plants during dark-induced leaf senescence when all three enzymes are expressed. Pairwise interactions and localization of the three enzymes were investigated using bimolecular fluorescence complementation (BiFC) with confocal microscopy in tobacco and sub-mitochondrial fractionation in Arabidopsis. Evidence for a complex composed of ProDH, P5CDH, and OAT was revealed by co-migration of the proteins in native conditions upon gel electrophoresis. Co-immunoprecipitation coupled with mass spectrometry analysis confirmed the presence of the P5C metabolism complex in Arabidopsis. Pull-down assays further demonstrated a direct interaction between ProDH1 and P5CDH. P5C metabolism complexes may channel P5C among the constituent enzymes and directly provide electrons to the respiratory electron chain via ProDH.

Organisationseinheit(en)

Institut für Pflanzengenetik

Externe Organisation(en)

Institute of Ecology and Environmental Sciences of Paris (iEES)
Université Paris Cité
Sorbonne Université

Typ

Artikel

Journal

Journal of experimental botany

Band

75

Seiten

917-934

Anzahl der Seiten

18

ISSN

0022-0957

Publikationsdatum

02.02.2024

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Physiologie, Pflanzenkunde

Elektronische Version(en)

https://doi.org/10.1093/jxb/erad406 (Zugang: Geschlossen)