What is the approximate distance at which BioID can ligate biotin to nearby proteins?

The correct answer indicates that BioID can effectively ligate biotin to nearby proteins at a distance of approximately 10 nm. BioID, or biotin identification, is a method that utilizes a biotin ligase (BirA) mutant, which can biotinylate proteins in proximity without requiring the proteins to be directly interacting in a complex.

The distance of 10 nm is significant because it reflects the typical range within which the enzyme can covalently modify nearby proteins, allowing for the identification of those that are in close spatial or functional proximity to a target protein. This range is well-suited for studying protein interactions in cellular environments, as many proteins operate within such distances in crowded cellular spaces.

Choosing this distance also highlights the versatility of the BioID technique in identifying potential interactors and mapping out interaction networks, as it allows researchers to look at proteins that may not necessarily be physically bound but are within a functional range that could imply a biological interaction. The options provided, especially those outside the 10 nm range, do not accurately reflect the established parameters of the BioID method and its capacity to tag neighboring proteins, making the 10 nm choice the most appropriate.