Fig. 5
From: The SAM domain of mouse SAMHD1 is critical for its activation and regulation
Model of mSAMHD1 allosteric activation. In the absence of nucleotides, mSAMHD1 primarily exists as inactive dimers that can associate to form loose inactive tetramers. After the first allosteric nucleotide binds, the rigid dimer components rearrange to form a more compact but inactive intermediate. Upon binding of the second allosteric nucleotide, mSAMHD1 rearranges further to form a catalytically active, compact tetramer
