3ZGE

Greater efficiency of photosynthetic carbon fixation due to single amino acid substitution

Summary for 3ZGE

• Entry DOI: 10.2210/pdb3zge/pdb
• Related: 3ZGB
• Descriptor: C4 PHOSPHOENOLPYRUVATE CARBOXYLASE, ASPARTIC ACID, SULFATE ION, ... (5 entities in total)
• Functional Keywords: lyase, c4 photosynthetic pathway, carbon fixation, pep carboxylase
• Biological source: FLAVERIA TRINERVIA
• Cellular location: Cytoplasm (By similarity): P30694
• Total number of polymer chains: 2
• Total formula weight: 227555.62

Authors

Paulus, J.K.,Schlieper, D.,Groth, G. (deposition date: 2012-12-17, release date: 2013-02-27, Last modification date: 2023-12-20)

Primary citation

Paulus, J.K.,Schlieper, D.,Groth, G.
Greater Efficiency of Photosynthetic Carbon Fixation due to Single Amino Acid Substitution
Nat.Commun., 4:1518-, 2013

PubMed Abstract: The C4-photosynthetic carbon cycle is an elaborated addition to the classical C3-photosynthetic pathway, which improves solar conversion efficiency. The key enzyme in this pathway, phosphoenolpyruvate carboxylase, has evolved from an ancestral non-photosynthetic C3 phosphoenolpyruvate carboxylase. During evolution, C4 phosphoenolpyruvate carboxylase has increased its kinetic efficiency and reduced its sensitivity towards the feedback inhibitors malate and aspartate. An open question is the molecular basis of the shift in inhibitor tolerance. Here we show that a single-point mutation is sufficient to account for the drastic differences between the inhibitor tolerances of C3 and C4 phosphoenolpyruvate carboxylases. We solved high-resolution X-ray crystal structures of a C3 phosphoenolpyruvate carboxylase and a closely related C4 phosphoenolpyruvate carboxylase. The comparison of both structures revealed that Arg884 supports tight inhibitor binding in the C3-type enzyme. In the C4 phosphoenolpyruvate carboxylase isoform, this arginine is replaced by glycine. The substitution reduces inhibitor affinity and enables the enzyme to participate in the C4 photosynthesis pathway.

PubMed: 23443546
DOI: 10.1038/NCOMMS2504

Experimental method

X-RAY DIFFRACTION (2.49 Å)