Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: UMLS:C1832526 (
PCC
)
5,967
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Phosphoenolpyruvate carboxylase (PEPc) is an essential enzyme in plants. A photosynthetic form is present both as dimer and tetramer in C4 and CAM metabolism. Additionally, non-photosynthetic PEPcs are also present. The single, non-photosynthetic PEPc of the unicellular cyanobacterium Synechococcus
PCC
7002 (Synechococcus), involved in the TCA cycle, was examined. Using size exclusion chromatography (SEC) and small angle X-ray scattering (SAXS), we observed that PEPc in Synechococcus exists as both a dimer and a tetramer. This is the first demonstration of two different oligomerization states of a non-photosynthetic PEPc. High concentration of Mg
2+
, the substrate
PEP
and a combination of low concentration of Mg
2+
and HCO
3
-
induced the tetramer form of the carboxylase. Using SEC-SAXS analysis, we showed that the oligomerization state of the carboxylase is concentration dependent and that, among the available crystal structures of PEPc, the scattering profile of PEPc of Synechococcus agrees best with the structure of PEPc from Escherichia coli. In addition, the kinetics of the tetramer purified in presence of Mg
2+
using SEC, and of the mixed population purified in presence of Mg
2+
using a Strep-tagged column were examined. Moreover, the enzyme showed interesting allosteric regulation, being activated by succinate and inhibited by glutamine, and not affected by either malate, 2-oxoglutarate, aspartic acid or citric acid.
...
PMID:Oligomerization and characteristics of phosphoenolpyruvate carboxylase in Synechococcus PCC 7002. 3210 4
Phosphoenolpyruvate carboxylase (PEPC) is the second major carbon-fixing enzyme in photoautotrophic organisms. PEPC is required for the synthesis of amino acids of the glutamate and aspartate family by replenishing the TCA cycle. Furthermore, in cyanobacteria, PEPC, together with malate dehydrogenase and malic enzyme, forms a metabolic shunt for the synthesis of pyruvate from
PEP
. During this process, CO
2
is first fixed and later released again. Due to its central metabolic position, it is crucial to fully understand the regulation of PEPC. Here, we identify PEPC from the cyanobacterium Synechocystis sp.
PCC
6803 (PEPC) as a novel interaction partner for the global signal transduction protein P
II
. In addition to an extensive characterization of PEPC, we demonstrate specific P
II
-PEPC complex formation and its enzymatic consequences. PEPC activity is tuned by the metabolite-sensing properties of P
II
: Whereas in the absence of P
II,
PEPC is subjected to ATP inhibition, it is activated beyond its basal activity in the presence of P
II
. Furthermore, P
II
-PEPC complex formation is inhibited by ADP and PEPC activation by P
II
-ATP is mitigated in the presence of 2-OG, linking PEPC regulation to the cell's global carbon/nitrogen status. Finally, physiological relevance of the in vitro measurements was proven by metabolomic analyses of Synechocystis wild-type and P
II
-deficient cells.
...
PMID:Phosphoenolpyruvate carboxylase from the cyanobacterium Synechocystis sp. PCC 6803 is under global metabolic control by P
II
signaling. 3227 33
