Question

One molecular marker of nitric oxide modification of proteins is a. 8-hydroxyguanosine (8-OHG) b. 4-hydroxy-2-nonenal (HNE) c. 3-nitrotyrosine (NT) d. 8-hydroxy-2'-deoxyguanosine (8-OHdG)

Short answer

a. 8-hydroxyguanosine (8-OHG) b. 4-hydroxy-2-nonenal (HNE) c. 3-nitrotyrosine (NT) d. 8-hydroxy-2'-deoxyguanosine (8-OHdG) Answer: c. 3-nitrotyrosine (NT)

Step-by-step solution

Identify the Correct Option

To find the right answer, we need to determine which of the given options is associated with nitric oxide modification of proteins. a. 8-hydroxyguanosine (8-OHG) is an oxidatively modified nucleoside that is a marker of oxidative DNA and RNA damage. b. 4-hydroxy-2-nonenal (HNE) is a product of lipid peroxidation, which occurs due to oxidative stress. c. 3-nitrotyrosine (NT) is a protein modification that is formed by the reaction of tyrosine residues with the reactive nitrogen species (RNS) such as peroxynitrite. Nitric oxide contributes to the formation of RNS and this option is a direct molecular marker of nitric oxide modification of proteins. d. 8-hydroxy-2'-deoxyguanosine (8-OHdG) is an oxidatively damaged DNA marker that measures levels of oxidative stress in cells. The correct option is #tag_answer#c. 3-nitrotyrosine (NT)#tag_end_answer# as it is a molecular marker of nitric oxide modification of proteins.

Key concepts

Molecular Markers

Molecular markers are special molecules used by scientists to detect specific biological changes or processes within a cell or tissue. They function like a "fingerprint" that indicates a specific biological event has occurred. For example, when proteins are modified by nitric oxide, molecular markers can help identify this modification.

• In the context of nitric oxide modification, 3-nitrotyrosine (NT) is a commonly recognized molecular marker.
• NT forms when tyrosine, an amino acid, reacts with reactive nitrogen species (RNS) like peroxynitrite, which are generated when nitric oxide is present.
• This marker is specifically important for scientists studying the effects of oxidative stress related to nitric oxide.

Molecular markers like NT provide researchers with insights into cellular mechanisms, diagnosing diseases, and evaluating the effectiveness of therapeutic interventions.

Protein Modification

Protein modification is a vital process where changes are made to proteins after they are produced in the cell. These changes can affect the protein's function, stability, and location within the body. Modifications can be introduced in response to various cellular signals or environmental changes, including those influenced by reactive species such as nitric oxide.

• Nitric oxide can lead to a modification known as nitration, particularly affecting the amino acid tyrosine.
• This nitration results in the formation of 3-nitrotyrosine, altering the protein's function and potentially impacting cellular communication pathways.
• Modifications like these are essential for regulating protein activity and can also serve as indicators of cellular stress or damage.

Understanding protein modifications, such as those induced by nitric oxide, helps scientists unravel complex biological processes and identify potential therapeutic targets for diseases where these modifications are prevalent.

Reactive Nitrogen Species

Reactive nitrogen species (RNS) are highly reactive molecules that are derived from nitric oxide and other nitrogen-containing compounds. These species can react with various cellular components, including proteins, lipids, and nucleic acids, altering their structure and function. This process is part of normal cellular regulation but can become harmful when produced in excess.

• Examples of RNS include peroxynitrite and nitrogen dioxide, which can attach to proteins and lead to modifications such as nitration.
• RNS are involved in signaling pathways but also play a role in cellular damage often linked to stress and inflammation.
• Balance is crucial; while RNS are necessary for physiological signaling, excess can contribute to pathologies, such as neurodegenerative diseases and cancer.

By studying reactive nitrogen species, scientists can better understand their dual role in health and disease, informing the development of strategies to mitigate their harmful effects.