Photosynthesis research offers support for low-valence paradigm

A new Yale study aims to settle a longstanding question about photosynthesis, the process by which plants convert sunlight into fuel, with oxygen as a byproduct.

For 40 years, scientists have debated about a mechanism relating to Mn₄Ca, a manganese “cofactor” within photosynthesis that acts like a high-performance solar battery. In that time, two schools of thought have emerged: those who think Mn₄Ca’s storage mechanism works via a low-valence paradigm (LVP) and those who think it occurs via a high-valence paradigm (HVP). (Valence refers to an atom’s capacity to combine with other atoms.)

The distinction is important, researchers say, because it may affect how engineers try to mimic photosynthesis in solar technologies.

Jimin Wang, a research scientist in the Department of Molecular Biophysics and Biochemistry in FAS, lands definitively on the LVP side. In a new study published in the Proceedings of the National Academy of Sciences, Wang conducted a Cryo-EM (cryogenic electron microscopy) analysis of proteins that contain Mn₄Ca—an approach that Wang said gives a more accurate picture than other analytic techniques.

“Resolving the longstanding LVP/HVP controversy could help chemists and engineers to design biology-inspired solar capture devices with greatly improved efficiency,” Wang said.