Specific labeling strategies

Labeling with fluorescent phalloidins may be combined with immunostaining. In this case, the phalloidin-staining solution can be applied in a mixture with fluores-cently labeled secondary antibodies. Combination of immunostaining with fluorescent phalloidins and fluorescently counterstained nuclei are extremely useful in multiple labeling strategies to locate antigens of interest with specific components of the cell. 

While general labeling strategies relying on expression of proteins using hydrolyzates of algae are useful for uniform or amino acid-specific labeling, expression can also be performed in minimal media in a cost-effective manner. These types of expression media... 

Based on our current understanding of ribosomal protein synthesis, several strategies have been developed to incorporate amino acids other than the 20 standard proteinogenic amino acids into a peptide using the ribosomal machinery . This allows for the design of peptides with novel properties. On the one hand, such a system can be used to synthesize nonstandard peptides that are important pharmaceuticals. In nature, such peptides are produced by nonribosomal peptide synthetases, which operate in complex pathways. On the other hand, non-natural residues are a useful tool in biochemistry and biophysics to study proteins. For example, incorporation of non-natural residues by the ribosome allows for site-specific labeling of proteins with spin labels for electron paramagnetic resonance spectroscopy, with... 

It is also well known that proteins differ in their abilities to be chemically stained and it would be very difficult to devise a set of calibration curves for every protein on an array. The heterogeneity of protein structure makes it unlikely that a general protein labeling strategy can be applied to arrays (Kodadek, 2001). Direct labeling may also alter protein structure, leading to denaturation or the inability to form a complex with a specific capture agent. While antibody stability on arrays appears adequate, other proteins may... 

The noncovalent specific labeling of NA probes based on the aptamer strategy has also been reported. The malachite green (37) aptamer, which was designed as a binary probe, assembles only in the presence of the target sequences and induces an increase in the intensity of the signal emitted by the F bound aptamer. 

This approach can be extended to larger targets by the TROSY experiment in combination with different labeling strategies (e.g., selective labeling of specific amino acids or deuteration). Deuteration replaces the nonexchangeable atoms by H, which thereby reduces T2 relaxation significantly... 

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