Question

Which of the following in vitro technique is used to find Protein-Protein Interaction

• A. Yeast-two hybrid
• B. In-situ hybridization
• C. Fluorescent Radio-recovery after Photobleach (FRAP)
• D. Western Blotting

Hint:

When answering questions about techniques, focus on the primary purpose of each method. Yeast-two hybrid = Protein-Protein Interaction. In situ hybridization = Nucleic Acid Location. Northern/Southern/Western Blot = RNA/DNA/Protein Detection. FRAP = Molecular Mobility.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The question asks to identify a technique used to study protein-protein interactions (PPIs) from the given list, with the specific condition that it is an "in vitro" technique. It is important to distinguish between in vitro (in a test tube, outside a living organism), in vivo (in a living organism), and in situ (in its original place).
Step 2: Detailed Explanation:
Let's analyze the options:
1. Yeast-two hybrid (Y2H): This is a powerful and very common molecular biology technique specifically designed to discover protein-protein interactions. It works by exploiting the modular nature of transcription factors in yeast cells. Two proteins of interest are fused to the separate domains of a transcription factor. If the proteins interact, they bring the domains together, reconstituting the transcription factor and activating a reporter gene. This process occurs inside a living yeast cell, making it technically an in vivo method. However, among the choices provided, it is the most direct and widely recognized method for discovering PPIs. It is likely the intended answer despite the inaccurate "in vitro" descriptor, which may be an error in the question.
2. In-situ hybridization: This technique is used to detect and localize specific nucleic acid (DNA or RNA) sequences, not protein interactions.
3. FRAP: This microscopy technique measures the dynamics and mobility of fluorescently labeled molecules within a living cell (in vivo). While it can provide indirect evidence of interactions (e.g., if a protein becomes less mobile upon binding to a large complex), it is not a direct method for finding PPIs.
4. Western Blotting: This technique is used to detect specific proteins in a sample. By itself, it does not detect PPIs. However, it is a crucial detection step in other techniques that do, such as Co-immunoprecipitation (Co-IP), which is an in vitro method. But Western Blotting alone is not the interaction-finding technique.
Step 3: Final Answer:
The Yeast-two hybrid system is the most famous and direct technique for identifying protein-protein interactions listed. Although it is an in vivo technique, its prominence in the field of PPI discovery makes it the most plausible intended answer, assuming the "in vitro" qualifier in the question is an error.