Back to David's theory of evolution: God's error corrections (Evolution)

by David Turell , Wednesday, August 26, 2020, 20:51 (1548 days ago) @ David Turell

An example of required protein beneficial folding:

https://phys.org/news/2020-08-protein-unprecedented-bacteria-uptake-thiosulfate.html

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"A new study led by researchers at Nara Institute of Science and Technology (NAIST), Nara, Japan, published in Science Advances, reports the crystal structure of YeeE, a membrane protein that allows bacteria to uptake thiosulfate from the environment in order to synthesize L-cysteine. The structure reveals that YeeE has a characteristic hourglass shape that results in a sophisticated mechanism for the uptake, providing fundamental information that could greatly lower cysteine production costs in industry.

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"...sulfur-based molecules like L-cysteine are essential for many of our proteins.

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"Bacteria can take up both sulfate and thiosulfate ions from the environment in order to synthesize L-cysteine. The efficiency of the synthesis from thiosulfate is higher because of fewer chemical reaction steps. To examine which proteins are crucial for thiosulfate uptake, the researchers conducted a series of genetic studies, finding YeeE.

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"'Both the inner and outer surfaces of YeeE are indented toward the center. We think this shape is crucial for initiating the uptake and conducts thiosulfate," explains Dr. Yoshiki Tanaka, the first author of the study.

"Molecular dynamics simulations implied that the uptake occurs by passing the thiosulfate ion through three key sites in the YeeE structure. In the model, the first site attracts a thiosulfate ion to the positively charged surface. Then using S-H-S type hydrogen bonds, YeeE passes the ion to the other two sites and on to the cytoplasm without itself undergoing any major conformational changes.

"This mechanism for uptake is quite unusual among membrane transporters according to Tanaka.

"'There is a lot less movement compared with transporters that have inward- and outward-facing structures or use rocking bundle motions. YeeE is not structurally designed to use these other mechanisms," he says."

Comment: the exact requirement for this exact shape makes my point. If the molecule fails to make this shape, its function is gone.