Final answer:
Histidine tagging and nickel columns are used in protein purification methods to isolate proteins with high affinity. They are not related to PCR, Western blot, or Gel electrophoresis as standalone techniques but can be complementary to protein-related workflows like Western blotting.
Step-by-step explanation:
Histidine tagging and nickel columns are a part of protein purification processes. When a protein is engineered to include a histidine tag, this tag enables the purification of the protein using a nickel column because the histidine residues bind to the nickel ions with high affinity. The bound protein can then be eluted with imidazole or by lowering the pH, thus separating it from other components in the sample that do not bind as strongly.
Western blotting is a technique that involves the separation of proteins by gel electrophoresis, followed by the transfer of these proteins onto a membrane, and the subsequent detection using specific antibodies. It is a form of immunoblot assay used for the detection and quantification of specific proteins within a sample.