Final answer:
Ni-NTA purification requires nickel ions to bind to His-tagged proteins and nitrilotriacetic acid (NTA) as a chelating agent to hold the nickel ions. Both components are crucial for the purification process.
Step-by-step explanation:
The question pertains to the components required for Ni-NTA purification, a technique often used in biochemistry and molecular biology for purifying proteins that have a histidine tag (His-tag). PET101D, the context provided in the question, seems to refer to a particular type of plasmid or expression vector commonly used in such purifications.
In Ni-NTA purification, both nickel ions and nitrilotriacetic acid (NTA) are crucial. Nickel ions are used to create a charged environment that binds to the His-tag on proteins, while NTA is the chelating agent that holds the nickel ions in place, allowing them to interact with the His-tagged proteins. Hence, the correct answer is option 3) Both A and B.