Photosynthesis For Green Fuel

To mimic the manganese-calcium (Mn₄Ca) catalyst-cluster found in photosystem II of plants, algae, and cyanobacteria is a major challenge for scientists seeking efficient ways to generate green fuels. "Harnessing Light" is a colorful article that reminds us of the high complexity involved in biological systems and how, throughout history, people have benefited from the study of nature by imitating and applying some of nature's potential in innumerable ways (C&EN, April 13, page 46).

The article is mostly accurate; however, one important correction needs to be made: Although photosynthesis in plants occurs in the chloroplasts, the protein complexes PSII and PSI, which account for the light reaction, are not located in its membrane but rather are embedded in the membrane of thylakoid disks inside chloroplasts. Only in this manner can a proton motive force be generated for subsequent formation of ATP inside the chloroplast (stroma).

Alberto Padilla
Aventura, Fla.