What happens in the third step of the type I topoisomerase reaction?
A. The enzyme changes to the open conformation.
B. The unbroken DNA strand passes through the break in the first strand.
C. Active-site tyrosine acts as a nucleophile and attacks one strand to form an enzyme-linked intermediate.
D. The enzyme changes to the closed form.
E. The 3' OH of the broken strand attacks the link between the active site tyrosine and the 5' end of the broken strand, resulting in religation of the broken strand.
B
You might also like to view...
Which cells are targeted by insulin?
a. skeletal muscle cells b. liver cells c. fat cells d. all of these cells are targeted by insulin e. only one of these cells is targeted by insulin
Language and abstract thought are possible due to the ____
a. cerebellum b. pons c. cerebral cortex d. medulla oblongata
e. midbrainWhich of the following characteristics of light is most commonly used for defining light as a portion of the electromagnetic spectrum?
a. the fact that all living organisms can detect it b. the fact that plants can detect it c. the fact that humans can detect it with their eyes d. the fact that non-human animals can detect it with their eyes
A hot, dry summer will reduce crop yields in part because
A) carbon dioxide release is reduced by the stomata closing to prevent excessive water loss. B) carbon dioxide uptake is reduced by the stomata closing to prevent excessive water loss. C) oxygen uptake is reduced by the stomata closing to prevent excessive water loss.