Final answer:
The Western blot detects specific proteins in a sample by using antibodies. It confirms the presence of a recombinant protein and can be modified to study protein-DNA or protein-protein interactions. However, it may yield indeterminate results in certain situations such as HIV diagnosis.
Step-by-step explanation:
The Western blot is an analytical technique used to detect specific proteins in a given sample. After proteins have been separated via gel electrophoresis (PAGE), they are transferred to a nitrocellulose membrane where they are probed with antibodies specific to the target protein. The primary antibody binds to the protein of interest, and a secondary antibody, tagged with an enzyme or fluorophore, binds to the primary antibody. The presence of the specific protein is then visualized through the enzymatic reaction with a chromogenic substrate or fluorescence, allowing for the detection and analysis of the protein.
In the context of recombinant proteins, the Western blot can confirm the presence and size of the expressed protein. It can also be adapted to study protein-DNA interactions (southwestern blot) or protein-protein interactions (far-western blot). However, in the case of HIV diagnosis for example, Western blot can sometimes give indeterminate results, which are neither clearly positive nor negative, due to cross-reactivity or previous viral infections, vaccinations, or autoimmune diseases.