English: "Stabilisation of the αC helix during activation of kinases. There are many kinases that are activated by extra domains or separate subunits. One of the ways this is achieved is through stabilisation of the αC helix, thus promoting a conformation that is conducive for efficient ATP binding, phosphate transfer and ADP release. For example, CDKs are activated by cyclin binding as a result of stabilisation of the CDK kinase domain αC helix by helix α5 of the Cyclin protein (PDB ID: 1QMZ, right panel). αC helix (CDK) and C-interacting helix (Cyclin) are coloured blue to highlight these regions. In our new structure of AMPK (left panel), a helix extending from the CBM packs against the α2 kinase domain αC helix (the C-interacting helix and αC helix are coloured red). This interaction is important for mediating the allosteric activation of AMPK by compounds. The structures are superposed in the lower panel." Supplementary Figure 8 from B.Xiao et al. "Structural basis of AMPK regulation by small molecule activators" Nature Communications 4 doi:10.1038/ncomms4017 . Image and description copied under CC-BY 3.0 licence.