Berkeley Lab researchers shine light on photosynthetic enzyme, future of bioproducts

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After almost three years of research, scientists at Lawrence Berkeley National Laboratory, or Berkeley Lab, used a new electron-counting camera to capture the structure of an important protein complex that plays a significant role in the photosynthesis process.

The scientists photographed NDH — an enzyme in the photosynthesis pathway. This discovery will allow researchers to further explore the function of NDH in photosynthesis and potentially make bioproducts such as bioplastics and fuels.

“We want to reduce our reliance on fossil fuels and reduce CO2 from the atmosphere,” said lead researcher Karen Davies.

Known to help regulate the carbon-fixation phase of photosynthesis, NDH works as an intermediary in the process of “converting high energy electrons into ATP,” an organic energy compound, according to first author Thomas Laughlin in an email.

NDH has been recognized for decades and been used in many experiments. Revealing the structure of the enzyme “puts a face to the name,” according to Laughlin’s email.

“The structure of NDH provides a new framework to rationalize decades of experimental results on the complex,” Laughlin said in the email.

Davies and Laughlin analyzed the structure of the enzyme with an electron-counting camera created in part with LBNL, according to Berkeley Lab news center. The electron-counting camera launched in 2012 and was first used in 2013, according to Davies.

Before this camera, researchers were only able to get about 50 images a day, according to Davies. Now, researchers are able to capture 1,000 to 2,000 images a day with one image containing up to 30 to 40 frames.

Instead of taking single images, the camera takes a “movie,” according to Davies. It then detects the electrons and captures where they hit the camera. The new camera procures images that are “crisp, sharp and higher resolution,” according to Davies.

Before the recent images, only one protein binding site for electron transfer was located on NDH. However, the new images reveal two binding sites for the electron transfer. These are the two binding sites that NDH needs “to complete its catalytic cycle in a timely fashion,” according to Laughlin in the email.

Some of the basic strategic goals of the project are to understand photosynthesis better and to use that information to make bioproducts, according to lead scientist Karen Davies. Bioproducts are important alternatives to plastics because they are renewable, and do not contaminate the atmosphere, according to Davies.

“Bioplastics are purer. They are renewable, not contaminating (the) atmosphere,” said Davies.

ASUC Senator Anna Whitney does not have an opinion on the project, but recognizes its potential implications for both campus and global sustainability goals.

“It sounds really promising and it could have major implications for our campus zero-waste goals and for zero waste globally,” said Whitney.

Contact Brennan Havens at [email protected] and follow him on Twitter at @BrennanHavens.