What is a common application of cross-linking reagents?

Cross-linking reagents are commonly used to reveal inter- and intra-molecular organization of amino acids within proteins. When proteins are treated with cross-linking agents, covalent bonds are formed between specific amino acid residues, which can stabilize the three-dimensional structure or facilitate the analysis of complex protein-protein interactions. This means that one can observe how proteins are organized with respect to each other, which is essential for understanding their function and interaction networks within cells.

By using cross-linking reagents, researchers can gain insights into the spatial arrangements of amino acids, both within a single protein (intra-molecular) and between different proteins (inter-molecular). This can be particularly useful in studying protein complexes, identifying binding partners, or mapping interaction sites that are crucial for biological function.

The other choices do not align with the primary purpose of cross-linking reagents. Denaturing proteins would disrupt their structure rather than revealing their organization. Enhancing signal detection in gels is more related to staining methods rather than cross-linking. Labeling proteins with fluorescent tags typically involves tagging techniques that are separate from cross-linking procedures. Thus, the use of cross-linking reagents specifically ensures a deeper understanding of protein structure and interactions.