New research published in the Proceedings of the National Academy of Sciences has outlined the procedure to gauge the strength of hydrogen bonds in proteins, the building blocks of life.
The study was conducted by the University of Wisconsin-Madison biochemists led by John Markley, Professor of biochemistry. The research focused on iron-sulfur proteins called rubredoxins. These proteins are vital for the electron transfer of energy throughout the living systems. They also play an important role in the transfer of energy in the photosynthetic and respiratory processes. "Variants of rubredoxin have evolved different sequences to transport electrons in the most efficient manner possible. Different mechanisms have been put forward to explain this, and we wanted to understand how the proteins evolved to have different electron affinities," Markley said.
In order to determine the strength of the hydrogen bonds in this protein, Markley's team that included graduate student I-Jin Lin, used nuclear magnetic resonance spectroscopy. This technique allowed them to monitor signals from atoms in the proteins, which in turn allowed them to accurately assess the location and strength of the hydrogen bonds in the protein. "Proteins are coded for by the genes in DNA. We'd like to be able to start with a gene sequence and predict the structure of a protein and its function. In this case, given an NMR pattern, we can tell you how the protein will act. In general, this method may provide information about even more complex biological systems. This is an approach that will be important for larger proteins," Markley explained.