Specific Protein Interactions

Figure Bl.20.10. Typical force curve for a streptavidin surface interacting with a biotin surface in an aqueous electrolyte of controlled pH. This result demonstrates the power of specific protein interactions. Reproduced with pennission from [81].

After assessing the interesting optical properties of the complexes, specific protein interactions with ConA as a model lectin were investigated in preliminary... 

Ligand-bound corticosteroid receptors have been shown to interact to form heterodimers with other transcription factors, such as the jun protein. Such interactions are responsible for transactivation of the ds-regulatory sites known as AP-1 sites and for the glucocorticoid-mediated suppression of transcription, such as that seen in the pro-opiomelanocortin gene. A number of such specific protein interactions have been reported these interactions and their locations relative to other transcription factors transform a ubiquitous steroid hormone signal into a tissue-specific, graded cellular response. 

ProteinChip arrays with preactivated surfaces are also available for covalently coupling of a specific bait molecule (protein, DNA, RNA). This allows the investigation of specific protein interactions such as DNA-protein, receptor-ligand, and antibody-antigen (Ab-Ag), the latter of which permits the generation of a standard curve and hence quantitation studies (21). 

The attachment of protein to the transducer surface for immunoassay is a difficult problem, since it must be achieved without interfering with the active site. If an unlabeled assay is to be performed it must also be such that subsequent non specific interaction with the surface can be inhibited. This requirement is often contrary to those for effective antibody-antigen complex formation. A surface close packed with antibody will be sterically hindered and its reaction with antigen inhibited. On the other hand, a suitably spaced packing allows non-specific interactions to occur and large false positive signals to be recorded. As mentioned earlier, this was demonstrated by Cullen and Lowe who used the surface plasmon resonance technique to probe specific and non-specific protein interactions at metal surfaces. (23). 

Since an EG (or OEG, alike) SAM is the base layer of the supramolecular architectures of almost all the protein interaction studies presented here, the absence of NSB on such a matrix enables a good start for the observation of specific protein interactions. 

Sometimes it is useful to apply a combination of the descriptors based on the global properties of the molecule and those based on a pharmacophoric representation. Conceptually, the global properties would better describe the imtial passive membrane permeation required to reach the site of action. Then, the specific protein interactions could be explained by the pharmacophoric descriptors. This has been demonstrated successfully in the P-glycoprotein case [26], where two processes are important for the transport passive transport to the cell and active... 

Histone acetylation is a hallmark of open and accessible chromatin structure, which results in activation of gene transcription. Histone acetylation leads to the recruitment of a number of bromodomain-containing proteins (BRDs) that exclusively recognize e-Af-acetylated lysine residues. These specific protein interaction modules, also called epigenetic reader domains, are evolutionarily highly conserved. The human proteome encodes 61 bromodomain interaction domains present in 42 proteins comprising chromatin modifying enzymes (histone... 

Specific Protein Interactions as a Possible Explanation for Unexpected Behavior of Blood at Interfaces... 

---