TY - JOUR
T1 - Posttranslational modification of the NADP-malic enzyme involved in C4 photosynthesis modulates the enzymatic activity during the day
AU - Bovdilova, Anastasiia
AU - Alexandre, Bruno M.
AU - Höppner, Astrid
AU - Luís, Ines Matias
AU - Alvarez, Clarisa E.
AU - Bickel, David
AU - Gohlke, Holger
AU - Decker, Christina
AU - Nagel-Steger, Luitgard
AU - Alseekh, Saleh
AU - Fernie, Alisdair R.
AU - Drincovich, Maria F.
AU - Abreu, Isabel A.
AU - Maurino, Veronica G.
PY - 2019/1/1
Y1 - 2019/1/1
N2 - Evolution of the C4 photosynthetic pathway involved in some cases recruitment of housekeeping proteins through gene duplication and their further neofunctionalization. NADP-malic enzyme (ME), the most widespread C4 decarboxylase, has increased its catalytic efficiency and acquired regulatory properties that allowed it to participate in the C4 pathway. Here, we show that regulation of maize (Zea mays) C4-NADP-ME activity is much more elaborate than previously thought. Using mass spectrometry, we identified phosphorylation of the Ser419 residue of C4-NADP-ME in protein extracts of maize leaves. The phosphorylation event increases in the light, with a peak at Zeitgeber time 2. Phosphorylation of ZmC4-NADP-ME drastically decreases its activity as shown by the low residual activity of the recombinant phosphomimetic mutant. Analysis of the crystal structure of C4-NADP-ME indicated that Ser419 is involved in the binding of NADP at the active site. Molecular dynamics simulations and effective binding energy computations indicate a less favorable binding of the cofactor NADP in the phosphomimetic and the phosphorylated variants. We propose that phosphorylation of ZmC4-NADP-ME at Ser419 during the first hours in the light is a cellular mechanism that fine tunes the enzymatic activity to coordinate the carbon concentration mechanism with the CO2 fixation rate, probably to avoid CO2 leakiness from bundle sheath cells.
AB - Evolution of the C4 photosynthetic pathway involved in some cases recruitment of housekeeping proteins through gene duplication and their further neofunctionalization. NADP-malic enzyme (ME), the most widespread C4 decarboxylase, has increased its catalytic efficiency and acquired regulatory properties that allowed it to participate in the C4 pathway. Here, we show that regulation of maize (Zea mays) C4-NADP-ME activity is much more elaborate than previously thought. Using mass spectrometry, we identified phosphorylation of the Ser419 residue of C4-NADP-ME in protein extracts of maize leaves. The phosphorylation event increases in the light, with a peak at Zeitgeber time 2. Phosphorylation of ZmC4-NADP-ME drastically decreases its activity as shown by the low residual activity of the recombinant phosphomimetic mutant. Analysis of the crystal structure of C4-NADP-ME indicated that Ser419 is involved in the binding of NADP at the active site. Molecular dynamics simulations and effective binding energy computations indicate a less favorable binding of the cofactor NADP in the phosphomimetic and the phosphorylated variants. We propose that phosphorylation of ZmC4-NADP-ME at Ser419 during the first hours in the light is a cellular mechanism that fine tunes the enzymatic activity to coordinate the carbon concentration mechanism with the CO2 fixation rate, probably to avoid CO2 leakiness from bundle sheath cells.
UR - http://www.scopus.com/inward/record.url?scp=85073087118&partnerID=8YFLogxK
U2 - 10.1105/tpc.19.00406
DO - 10.1105/tpc.19.00406
M3 - Article
C2 - 31363039
AN - SCOPUS:85073087118
VL - 31
SP - 2525
EP - 2539
JO - Plant Cell
JF - Plant Cell
SN - 1040-4651
IS - 10
ER -