New research out of MIT has deciphered part of the bacterial communication network that has long frustrated scientists. The multitude of communication pathways in bacteria share common enzymes, yet they are still able to communicate without any interference or “crosstalk.” The MIT scientists were able solve this problem, and even program their own bacterial communication pathways, by finding pairs of amino acid co-evolution. Here’s more on the discovery from MIT:
“If an organism has tons of this class of signaling pathway, why do we not get a lot of crosstalk?” said Laub. “How does the kinase pick out the right target?”
Based on earlier studies, the MIT researchers theorized that the specificity of the interaction is determined by a subset of amino acids on the histidine kinase and a corresponding subset of amino acids on the response regulator.
To confirm their theory, they looked for patterns of amino acid co-evolution in pairs of histidine kinases and their target response regulators.
Co-evolution occurs when a mutation in one of the two proteins is followed by a secondary mutation in the corresponding amino acid on the other protein, allowing the protein pair to maintain their interaction.
After searching a vast database of nearly 1,300 protein pairs, they identified a small set of co-evolved amino acids. They then confirmed that these amino acids govern signaling specificity by successfully rewiring five of the pathways by mutating the target amino acids.
Such manipulation could allow scientists to engineer bacteria that exhibit novel behavior such as glowing when they detect the presence of a pollutant such as toluene, said Laub.
Cheap chemical sensors that you could simply grow in a beaker would be incredibly useful.
Press release: MIT researchers unravel bacteria communication pathways …
Image caption: Diagram shows the structure of a histidine kinase (blue ribbons) and its target response regulator (green ribbons). The specificity of the interaction between the two proteins is primarily determined by the orange and red amino acid residues.