Biochemistry question

Regulation of Ribonucleotide Reductase by Deoxynucleoside Triphosphates
Derek T Logan (2011) Nature Structure & Molecular Biology 
The regulation of Ribonucleotide Reductase (the enzyme responsible for the conversion of the four standard ribonucleotides to their 2-deoxyribonucleotide counterparts) is of prime importance. Please detail and fully describe the binding of effector molecules on the activity and specificity of this enzyme. Why is this unique type of regulation so critical?