To study how a signal (phosphorylation) travels through the RegA response regulator, Ganesh S. Anand, an assistant professor of biological science at National University of Singapore, and graduate student Balakrishnan S. Moorthy compared the hydrogen-deuterium exchange behavior of three states of the protein: unphosphorylated (inactive), phosphorylated (active), and active mutant (unphosphorylated). The video animation captures the relative mobilities (“heat”) of the proteins at various incubation periods: Blue indicates rigidity, and red indicates flexibility. Over a period of 10 minutes, phosphorylated RegA remains relatively inflexible, whereas unphosphorylated RegA and active mutant RegA display increasing floppiness. These behaviors suggest that phosphorylation stabilizes the functionally most active conformation of RegA. (J. Mol. Biol., DOI: 10.1016/j.jmb.2012.01.052).
Experiments to probe protein behavior get significant assist from instrument maker