Evolution of C4 Phosphoenolpyruvate Carboxylase: Enhanced Feedback Inhibitor Tolerance Is Determined by a Single Residue

Kranz and single-cell forms of C4plants in the subfamily Suaedoideae show kinetic C4convergence for PEPC and Rubisco with divergent amino acid substitutions

“…From species surveyed in Suaedoideae, the IC 50 values for MA indicate that it is an effective inhibitor of PEPC at mM levels ( Table 4 ). PEPC from C 3 Suaeda species was more sensitive to inhibition by MA (assayed either with or without G6P) which is consistent with other studies where C 4 PEPCs are generally reported to be more tolerant to MA compared with C 3 orthologous genes or paralogous genes ( Svensson et al , 1997 ; Dong et al , 1998 ; Blasing et al , 2002 ; Paulus et al , 2013a ). Among the C 4 Suaeda , the two Salsina Kranz species, had significantly higher IC 50 values indicating higher tolerance to MA (when assayed in the presence or absence of G6P), compared with the Schoberia Kranz species and the single-cell C 4 species S. aralocaspica.…”

Evolution of the Phosphoenolpyruvate Carboxylase Protein Kinase Family in C3 and C4 Flaveria spp.

“…has been studied extensively and the influence of crucial amino acid exchanges on enzymatic activity has been clarified (Bläsing et al, 2000;Engelmann et al, 2002Engelmann et al, , 2008Paulus et al, 2013aPaulus et al, , 2013b, no such information exists for PPCK at this time. Additionally, as the cumulative findings from previous and these studies reinforce the differences in phosphorylation patterns of PEPC from C 3 and C 4 species, and at a time with ongoing efforts for engineering C 4 traits in C 3 crops, we can only stress the need for detailed knowledge of the regulation of one of the key enzymes of the C 4 pathway.…”

“…Malate, Asp, and oxaloacetate function as negative feedback regulators, while the PEPC activity increases in the presence of triose and hexose phosphate (Rajagopalan et al, 1994;Law and Plaxton, 1997;Bläsing et al, 2002;Svensson et al, 2003;TakahashiTerada et al, 2005;Jacobs et al, 2008). The C 4 ppcA PEPC isoform has been shown to have a lower sensitivity for the allosteric inhibitors mentioned above, a characteristic that is explained by a single-amino acid mutation from Arg-884 to Gly (Paulus et al, 2013a(Paulus et al, , 2013b.…”

“…It included changes in the transcriptional regulation of genes that encode components of the C 4 pathway and the adjustment of enzyme properties and their regulation (Sheen, 1999;Sage, 2004;Akyildiz et al, 2007;Engelmann et al, 2008;Aubry et al, 2011;Brown et al, 2011;Ludwig, 2011;Wiludda et al, 2012;Paulus et al, 2013aPaulus et al, , 2013b. In the process of evolution toward C 4 photosynthesis, PEPC was influenced by a series of single-amino acid exchanges that raised the Michaelis-Menten constant for the substrate phosphoenolpyruvate (Bläsing et al, 2000) and lowered the sensitivity to malate and Asp (Engelmann et al, 2002;Paulus et al, 2013aPaulus et al, , 2013b. So far, there is no information if such exchanges have also occurred in the regulatory protein Phosphoenolpyruvate Carboxylase Protein Kinase (PPCK), whose phosphorylation of PEPC changes the kinetic and regulatory properties of the enzyme (Nimmo, 2003).…”

Pyrazolidine‐3,5‐dione‐based inhibitors of phosphoenolpyruvate carboxylase as a new class of potential C4 plant herbicides

“…S2). The smaller residues have been linked with a weaker feedback inhibitor‐binding site , for example, G884 in PEPC of the C 4 plant Flaveria trinervia does not show any interaction with the inhibitor . Recently, we used the molecular difference in the feedback inhibitor‐binding site of PEPC between C 3 and C 4 plants to develop potential C 4 plant‐selective herbicides with a novel mode of action .…”