In ribonucleotide reductase protein R1 from Escherichia coli this domain is located at the N terminus, and is composed mostly of helices.[2] It forms part of the allostericeffector region and contains the general allosteric activity site in a cleft located at the tip of the N-terminal region.[3] This site binds either ATP (activating) or dATP (inhibitory), with the base bound in a hydrophobic pocket and the phosphates bound to basic residues. Substratebinding to this site is thought to affect enzyme activity by altering the relative positions of the two subunits of ribonucleotide reductase.
The ATP-cone domain also is a key part of NrdR, that controls transcription of ribonucleotide reductases in bacteria, in response to ATP and dATP levels. [4]
References
^Aravind L, Wolf YI, Koonin EV (April 2000). "The ATP-cone: an evolutionarily mobile, ATP-binding regulatory domain". J. Mol. Microbiol. Biotechnol. 2 (2): 191–4. PMID10939243.