Figure 4.

Multisite phosphorylation affects protein structure and function. (A) Multisite phosphorylation, particularly around the flexible protein regions, affects protein–protein interactions and local/global protein structure. (B) The multisite phosphorylation process could be a period-determining step in eukaryotic circadian clocks. Reaction rates of the kinases responsible for these events can be temperature-insensitive. This abstractive principle may be compatible with the design principle of cyanobacterial circadian-period determination (see Fig. 2C).