The question of how some of the algal enzymes reach a high level of hydrogen transfer proton production have been speculative in the past. Dr. Martin Winkler, dr. Jifu Duan, professor Eckhard Hofmann and professor Thomas Happe of the Ruhr-Universität Bochum (RUB), along with colleagues from Freie Universität Berlin, followed the paths of protons to the active center [FeFe]-hydrogenase. Their findings would allow scientists to create stable chemical reproductions of such efficient but fragile biocatalysts. Researchers published their report in the magazine Nature of communication from November 9, 2018.
Unique transmission efficiency
In their catalytic center of hydrogen, they produce molecular hydrogen (H2) from two protons and two electrons. The protons required for this process are extracted from the surrounding water and transferred through the transport chain to their catalytic core. The precise proton path through the aquifer has not yet been understood. "This portable path is a puzzle that is essential to understanding the interaction of cofactor and proteins, which makes biocatalysts more effective than chemical complexes that produce hydrogen," says Dr. Martin Winkler, one of the authors of this study from the research group Photobiotechnology in the rubric.
The enzyme variant structures are decoded
In order to find out which of the hydrogenated building blocks are involved in the transfer of protons, researchers have been individually replaced. They were replaced by either an amino acid with a similar function or a dysfunctional amino acid. So we created 22 versions of two different hydrogen. Then, researchers compared these variations with respect to various aspects, including their spectroscopic properties and their enzymatic activity. "The molecular structures of the twelve protein variants that were solved by analyzing the X-ray structure proved to be particularly informative," says Winkler.
Amino acids with no function stop the hydrogenation
Depending on where and how the researchers changed the hydrogen, hydrogen production became less effective or completely stopped. "This is how we have discovered why some variants are seriously affected in terms of enzymatic activity and why others are not affected at all – against all expectations," says Martin Winkler.
Substituted amino acids were placed closer to the catalytic center; less capable of hydrogenation was to replace these changes. If sensitive blocks were installed without function, hydrogen production was stopped. "This state of affairs is reminiscent of the congestion due to gas stress, where protons and hydrogen are simultaneously being introduced into the aquifer," says Martin Winkler. "During the time of our project, for the first time we managed to stabilize and analyze this very transient situation that we have already encountered in experiments."
Valuable basic information
This study has allowed the assignment of functions of individual amino acids on the pathway for the transfer of protons to the enzyme group [FeFe] hydrogenation. "In addition, it provides valuable information on the molecular mechanism for the transfer of protons using redox-active proteins and their structural requirements," concludes Thomas Happe.
The project was funded by the Volkswagen Foundation, the Chinese Fellowship Council and the German Research Foundation under the auspices of the Resolv Cluster of Excellence (EXC1069).
The materials it provides Ruhr-University Bochum. Originally written by Meike Drießen; which was translated by Donata Zuber. Note: You can edit the content for style and length.