Identification of the active site of HetR protease and its requirement for heterocyst differentiation in the cyanobacterium Anabaena sp. strain PCC 7120

Results indicate that Ser152 is the active site of serine-type protease, HetR, of Anabaena. Data also point out that the protease component is involved in the heterocyst differentiation as well as for repressing HetR overproduction when nitrogen deprivation conditions prevail.