Protein-surface interactions spectrometry

The techniques developed to study protein interactions can be divided into a number of major categories (Table 31.1), including bioconjugation, protein interaction mapping, affinity capture, two-hybrid techniques, protein probing, and instrumental analysis (i.e., NMR, crystallography, mass spectrometry, and surface plasmon resonance). Many of these methods are dependent on the use of an initial bioconjugation step to discern key information on protein interaction partners. 

This proposal describes the development of a new, systematic approach for qualitatively and quantitatively studying surface-biomolecule interactions by matrix-assisted laser desorption ionization (MALDl) mass spectrometry (MS). This methodology is being developed because of the profound importance that surface-biomolecule interactions play in applications where biomaterials come into contact with complex biological fluids, it can readily be shown that undesired reactions occurring in response to surface-biomolecule contact (protein adsorption, biofouling, immune response activation, etc.) lead to enormous economic and human costs. Thus, the development of analytical methodologies that allow for efficient assessment of the properties of new biomaterials and/or the study of detailed fundamental processes initiated upon surface-biomolecule contact are of critical value ... 

Analytical Applications of MAEDI Mass Spectrometry to the Study of Surface-Protein Interactions (from Kinsel, 1999)... 

Another use for combinatorial libraries has been the screening of peptides for antimicrobrial properties. In this case, the design of the library is based on antimicrobial peptides found in nature. A combinatorial synthesis is used to find alternative unnatural amino acids expected to mimic the antimicrobial properties.23 Peptide libraries also have been used to find compounds that could bind the lytic peptide mellitin.24 The library was synthesized in solution phase, purified, and evaluated using time-of-flight mass spectrometry (TOF-MS). The sequences determined to bind to mellitin contained hydrophobic pairs. By binding to mellitin, they were able to prevent the cell-surface mellitin interaction. This is an example of a peptide library able to afford compounds that interact with other small peptides without having to find an interacting protein first. 

The specific interaction of Cu ions with a 26-residue peptide present at the surface of a human protein has been studied by mass spectrometry [1], The positive ion electrospray spectra A and B (Figure 9.2) have been obtained, respectively, before and after addition of Cu(II). 

Bouffartigues E, Leh H, Anger-Leroy M, Rimsky S, Buckle M (2007) Rapid coupling of surface plasmon resonance (SPR and SPRi) and proteinchip based mass spectrometry for the identification of proteins in nucleoprotein interactions. Nucl Acids Res 35 e39... 

The use of protein microarrays has also made a big impact in the study of protein-protein interactions. In this method, thousands of proteins are spotted in a microarray format at known locations on a chip, then the solution of the target protein is spread on the chip. Interacting proteins are detected by fluorescent imaging, surface plasmon resonance, or mass spectrometry.174-177... 

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