EC Number   |
General Information |
Reference |
|---|
   2.7.4.27 | evolution |
PDRP shares no significant sequence similarity with other protein kinases or phosphatases |
739360 |
| 2.7.4.27 | evolution |
two loci for PPDK genes in maize chromosomes: one locus can transcribe two overlapping genes (C4 chloroplast PPDK [C4ppdk] and cytosolic PPDK [CyppdkZm1]) that are divergent at their 5' ends owing to different transcription initiation sites, isozyme sequences comparisons, the two peptides differ by 42 D, overview |
739352 |
| 2.7.4.27 | more |
PDRP forms a compact homodimer in which each protomer contains two separate N-terminal and C-terminal domains. The C-terminal domain includes several key elements for performing both phosphorylation and dephosphorylation activities: the phosphate binding loop (P-loop) for binding the ADP and inorganic phosphate substrates, residues Lys274 and Lys299 for neutralizing the negative charge, and residue Asp277 for protonating and deprotonating the target Thr residue of PPDK to promote nucleophilic attack. The N-terminal domain shares the same protein fold as the C-terminal domain and also includes a putative P-loop with AMP bound but lacking enzymatic activities. This loop may participate in the interaction with and regulation of enzyme PPDK. The N-terminal domain has conserved intramolecular and intermolecular disulfide bonds for PDRP dimerization. Three-dimensional structure analysis, overview |
739360 |
| 2.7.4.27 | more |
the two hydrogen bonds between the highly conserved residues Ser528 and Gly525 are required for enzyme PDRP-mediated phosphorylation of the active site residue Thr527 of PPDK |
739352 |
| 2.7.4.27 | physiological function |
in C4 plants, pyruvate orthophosphate dikinase (PPDK) activity is tightly dark/light regulated by reversible phosphorylation of an active-site threonine residue catalyzed by PPDK regulatory protein (PDRP). Phosphorylation and dephosphorylation of PPDK lead to its inactivation and activation of PPDK, respectively. Light intensity rather than the light/dark transition regulates PPDK activity by modulating the reversible phosphorylation at Thr527 of PPDK in Zea mays. The amount of unphosphorylated PPDK involved in C4 photosynthesis is strictly controlled by light intensity, despite the high levels of PPDK protein that accumulate in mesophyll chloroplasts. The regulation of maize plastid PPDK isoform (C4PPDK) activity is complex, overview |
739352 |
| 2.7.4.27 | physiological function |
PPDK regulatory protein (PDRP) regulates the inorganic phosphate-dependent activation and ADP-dependent inactivation of PPDK by reversible phosphorylation. Pyruvate orthophosphate dikinase (PPDK) is one of the most important enzymes in C4 photosynthesis |
739360 |
