The alteration of G to 8-oxo-G is significant because it can form what type of base pair?

• A. Watson-Crick base pairs
• B. Hoogsteen base pairs
• C. Stacked base pairs
• D. Pyrimidine pairs

Answer: (B)

The alteration of guanine (G) to 8-oxo-guanine (8-oxo-G) is significant in the context of DNA damage due to its ability to participate in Hoogsteen base pairing. Specifically, 8-oxo-G can pair with adenine through this alternative base-pairing arrangement. Hoogsteen base pairs are formed when the bases are oriented in a different conformation compared to the traditional Watson-Crick base pairing, which involves specific hydrogen bonding patterns.

This transformation from G to 8-oxo-G affects the stability of DNA and can lead to mutations if not repaired, as it can mispair with adenine instead of cytosine during DNA replication. The formation of Hoogsteen pairs reflects a unique characteristic of 8-oxo-G, highlighting its role in genomic instability and the importance of DNA repair mechanisms to maintain fidelity in genetic information.

Hoogsteen pairing is particularly relevant in the context of DNA damage response pathways that recognize and repair oxidative lesions. Understanding this type of base pairing is crucial when studying the implications of oxidative stress on genetic material and the mechanisms that cells employ to counter such alterations.