Question

The nucleoside analogue acyclovir, which is used to treat herpes simplex virus (HSV) infections, lacks a 3′ hydroxyl group (–OH). Predict what will happen if the host cell DNA polymerase incorporates a molecule of acyclovir into an elongating strand of HSV DNA.

Answer 1

Answer:

There won't be any functional viral DNA synthesis

Explanation:

First of all, you must consider that the HSV has a double-stranded, linear DNA genome. Furthermore, the DNA skeleton is made of the 5'-3' phosphodiester bond. In other words, the 5-phosphat of a nucleotide will bond the 3' OH of the Deoxyribose (see image).

Therefore, if you add a molecule which lacks the 3' OH, such as acyclovir, and has a similar chemical structure to a regular nucleotide, the DNA polimerase will be able to add acyclovir to the main backbone of the viral genome. All in all, you'd be ''cheating'' the DNA pol.

Hence, wherever acyclovir was integrated, there won't be any chance to form a 5'-3' phosphodiester bond. The protomolecule will not be stable and will soon be degradated.