9 by: Gurangi Benner-Tapia

Student – Gaurangi Benner-Tapia

Enzyme – ATP Synthase

E.C. Number – 7.1.2.2

Where is ATP Synthase found? In plants and animals, ATP synthase is found in the cristae of the mitochondria. In plants ATP synthase is additionally found in the thylakoid membrane of chloroplasts, while in bacteria and archaea it is found in the plasma membrane (Neupane, 2019).

What does ATP synthase do? ATP synthase phosphorylates ADP for it to be used as an energy source, being ATP. Phosphorylation of ADP is the process of “adding on” an extra phosphate group to the molecule, which is the main mechanism of ATP synthesis. This is done by exciting electrons (bringing it to a higher energy level), transporting those electrons on an electron transport chain (ETC), and using the electrochemical gradient caused by this energy transfer to phosphorylate ADP into ATP. In plants the process of exciting electrons occurs by the chloroplasts in the thylakoid membrane absorbing energy from sunlight. (Igamberdiev, 2015). There are two ends of ATP synthase. The Fo side of ATP synthase is embedded in the
lipid membrane, while the F1 end is exposed to the solvent (Dittrich, 2003). The proton gradient between the lipid membrane and the cytosol is the driving force of the reaction. There is a central stock that is connected to the F1 end of ATP synthase which is rotated by the Fo end. This rotation creates conformational change in binding pockets that are found in the F1 end of the enzyme, and this is how ATP is synthesized. (Dittrich, 2003).

References
Dittrich, M., Hayashi S., Schulten, K. (2003). On the mechanism of ATP hydrolysis in Fi-ATPase. Biophys J, 85 (4), 2253-2266. doi: 10.1016/S0006-3495(03)74650-5

Igamberdiev, A.U. & Kleczkowski, L.A. (2015). Optimization of ATP synthase function in mitochondria and chloroplasts via the adenylate kinase equilibrium. Front Plant Sci, 6 (10), . https://doi.org/10.3389%2Ffpls.2015.00010

Khan Academy. (2015). ATP hydrolysis mechanism [Video]. Youtube. https://www.youtube.com/watch?v=-KE7jTXwNYs

Neupane, P., et al. (2019). ATP Synthase: Structure, Function and Inhibition. Biomolecular Concepts, 10 (1),1-10. https://doi.org/10.1515/bmc-2019-0001

Information on EC 7.1.2.2 – H+-transporting two-sector ATPase. (2023). Brenda. https://www.brenda-enzymes.org/enzyme.php?ecno=7.1.2.2