NFR5 lacks the classical activation loop in the kinase domain.

The alpha subunits have the catalytic kinase domain.

That step is followed by side-to-side homo- and heterodimerisation of their now accessible kinase domains.

They have 65% amino acid sequences in common and 92% homology within their kinase domains.

There are at present no drugs on the market specially targeting phosphorylation sites, however, a number of drugs target the kinase domain.

Similarly, the extension in IfkA shows limited sequence identity to the kinase domain.

As a result, the activation loop changes conformation, stretching out across the C-lobe of the kinase domain.

The N-terminal kinase domain is able to phosphorylate histone H1.

The kinase domain is located on the N-terminal.

As a result the kinase domain is activated and phosphorylates eIF2α at Ser51.