Cell signaling enzymes-Neutrons show atomic structure

The direct clarifications of the working mechanism of an ideal kinase enzyme will give researchers and medicine developers considerably improved capabilities to address life-threatening ailments and neurological conditions such as cancer, cystic fibrosis etc.

An international group of researchers made the finding using the macromolecular neutron crystallography at the Department of Energy’s Oak Ridge National Laboratory and also the Institut Laue-Langevin- Grenoble. These exposed previously unidentified features of the typical protein kinase.

Kinases- a big group of enzymes accountable for regulating myriad cellular processes. Proteins receive signals by the kinases through phosphorylation (the process of addition of a reactive chemical group containing phosphorus and oxygen to a particular site on a substrate protein to activate its biological function).

Diseases occur when gene alterations cause kinases to operate imperfectly. A faulty kinase could prove to pave way for the uncontainable spread of cancer cells.

“This detailed understanding of the PKA structure and its dynamics will tell us more about other kinds of kinases and should help drug developers design new drugs with better specificity, which would ultimately translate to more precise therapeutics with fewer side effects” co-author Andrey Kovalevsky says.

Alterations in the protein construction because of mutations may be hard to identify. These manners become more apparent through examination of the hydrogen bonding along the protein.

Neutrons are reactive to lighter elements like hydrogen. Since about half of the atoms in proteins are hydrogen, and reactions that enzymes catalyze mostly consist of hydrogen, neutrons are perfect for identifying the location of hydrogen atoms in the protein and tracing their movements while catalysis.

Neutron diffraction made researchers able to appreciate the particular locations of hydrogen atoms to expose the overall assembly of the enzyme and the ligands which are bounded to its active sites.

“Neutrons enabled us to validate x-ray predictions of hydrogen atom positions, as well as determining the protonation states of chemical groups that were not known, or in places where we didn’t expect to find them. This major chemical advance paves the way for more sophisticated molecular modeling and simulation studies of protein kinase structure and function,” joint author Susan Taylor stated.

Gianluigi Veglia, also a co-author, says: “Neutrons offer an unprecedented view of the hydrogen bond network surrounding and within the active site of PKA and give crucial insights on how allosteric transmission of information through the protein structure occurs.”