Contrast the binding of nucleotides to the activity site and specificity site on the R1 subunit of E.coli ribonucleotide reductase by choosing the nucleotide that can bind to the specificity site but NOT the activity site.
A) ATP
B) dTTP
C) dATP
D) dCDP

Question

Quizplus · Accepted Answer

The specificity site on the R1 subunit of E.coli ribonucleotide reductase has a high affinity for dATP and dGTP, which binds and regulates enzyme activity. However, dTTP cannot bind to the activity site of R1 subunit, as it is not a substrate for the enzyme. Therefore, dTTP can only bind to the specificity site and not the activity site. On the other hand, ATP, dATP, and dCDP can all bind to the activity site of the enzyme, making them poor choices for this question.

Contrast the Binding of Nucleotides to the Activity Site and Specificity