What is the primary function of BioID in protein analysis?

The primary function of BioID in protein analysis is to create fusion proteins that ligate biotin to nearby proteins. BioID, or proximity-dependent biotin identification, is a technique used to study protein-protein interactions and protein localization within cells. By fusing a biotin ligase to a protein of interest, BioID allows for the capture of proteins that are in close proximity to that protein, effectively tagging them with biotin. This biotinylation makes it easier to isolate and identify these interacting proteins using streptavidin-based purification methods.

This method enhances our understanding of cellular pathways and protein dynamics by revealing which proteins are interacting in the context of their natural cellular environment. The ability to selectively label and then analyze proteins that are near the protein of interest is a significant advancement in biochemistry and cell biology, making BioID a powerful tool for researchers investigating complex biochemical interactions.

The other options do not accurately capture the unique function of BioID. For example, size exclusion chromatography is a method for separating proteins based on size, and quantifying enzyme activity relates more to enzymology than protein interaction studies. Purifying DNA samples does not pertain to the function of BioID, which specifically focuses on proteins and their interactions.