Details

Autor(en) / Beteiligte

• Stoffel, Gabriele M. M.
• Saez, David Adrian
• DeMirci, Hasan
• Vögeli, Bastian
• Rao, Yashas
• Zarzycki, Jan
• Yoshikuni, Yasuo
• Wakatsuki, Soichi
• Vöhringer-Martinez, Esteban
• Erb, Tobias J.

Titel

Four amino acids define the CO₂ binding pocket of enoyl-CoA carboxylases/reductases

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 2019-07, Vol.116 (28), p.13964-13969

Ort / Verlag

Washington: National Academy of Sciences

Erscheinungsjahr

2019

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• Carboxylases are biocatalysts that capture and convert carbon dioxide (CO₂) under mild conditions and atmospheric concentrations at a scale of more than 400 Gt annually. However, how these enzymes bind and control the gaseous CO₂ molecule during catalysis is only poorly understood. One of the most efficient classes of carboxylating enzymes are enoyl-CoA carboxylases/reductases (Ecrs), which outcompete the plant enzyme RuBisCO in catalytic efficiency and fidelity by more than an order of magnitude. Here we investigated the interactions of CO₂ within the active site of Ecr from Kitasatospora setae. Combining experimental biochemistry, protein crystallography, and advanced computer simulations we show that 4 amino acids, N81, F170, E171, and H365, are required to create a highly efficient CO₂-fixing enzyme. Together, these 4 residues anchor and position the CO₂ molecule for the attack by a reactive enolate created during the catalytic cycle. Notably, a highly ordered water molecule plays an important role in an active site that is otherwise carefully shielded from water, which is detrimental to CO₂ fixation. Altogether, our study reveals unprecedented molecular details of selective CO₂ binding and C–C-bond formation during the catalytic cycle of nature’s most efficient CO₂-fixing enzyme. This knowledge provides the basis for the future development of catalytic frameworks for the capture and conversion of CO₂ in biology and chemistry.