Protein array

The spatial arrangement of atoms in two-dimensional protein arrays can be detennined using high-resolution transmission electron microscopy [20]. The measurements have to be carried out in high vacuum, but since tire metliod is used above all for investigating membrane proteins, it may be supposed tliat tire presence of tire lipid bilayer ensures tliat tire protein remains essentially in its native configuration. 

Thin liquid films on a fluid surface were also employed for the construction of protein arrays [40]. The construction of a tightly chemically bound protein monolayer onto a solid support required detailed systematic study involving careful optimization of reaction conditions and comparison of the efficacy of several alternatives [46]. 

Isotope labeling Phage display Protein arrays Computational approaches... 

A variety of formats for protein arrays are possible. For example, a set of antibodies can be gridded on a filter or slide and used to detect protein expression levels (Pandey and Mann, 2000). Another type of array consists of proteins from an organism arrayed directly on to a glass slide, nylon filter or in microtiter wells (MacBeath and Schreiber, 2000). This format could be used to map protein-protein interactions or to associate a catalytic function with a protein. 

The difficulty with protein arrays is that proteins do not behave as uniformly as nucleic acid. Protein function is dependent on a precise, and fragile, three-dimensional structure that may be difficult to maintain in an array format. In addition, the strength and stability of interactions between proteins are not nearly as standardized as nucleic acid hybridization. Each protein-protein interaction is unique and could assume a wide range of affinities. Currently, protein expression mapping is performed almost exclusively by two-dimensional electrophoresis and mass spectrometry. The development of protein arrays, however, could provide another powerful... 

Functional analysis using peptide and protein arrays... 

Protein arrays may offer advantages over libraries. The array format provides a precise spatially oriented grid that allows side-by-side comparison of assay results for all of the proteins on the array. The spatial arrangement also permits immediate identification of a clone that tests positive in an assay based on its location on the array. Therefore, less effort is required to identify the protein responsible for an interaction than with a library screen. A disadvantage of a protein array, however, is that fewer proteins can be efficiently arrayed and screened ( 104) versus a library ( 109). Therefore, the number of elements that can be effectively arrayed and assayed currently limits protein arrays. 

Melton, L. Protein arrays proteomics in multiplex. Nature 2004,429,101-107. 

Emili AQ et al. Large-scale functional analysis using peptide or protein arrays. Nature Biotechnol 2000 18 393-397. Fung ET et al. Protein biochips for differential profiling. Curr Opin Biotechnol 2001 12 65-69. 

D protein arrays based on biotin-streptavidin architectures are likely to be the system of choice due to their ease in handling, excellent signal-to-noise ratio and non-specific interactions. 3D surfaces based on porous gold, sol-gel materials, polymer brushes and dextran surfaces are widely used to mimic the properties of bulk solution and increase the immobilization capacity of proteins. 

Though protein arrays borrow extensively from DNA-arrays, there are fundamental differences ... 

Copeland S., Siddiqui J., Remick D., Direct comparison of traditional ELISAs and membrane protein arrays for detection and quantification of human cytokines, J Immunol Methods 2004 284 99-106. 

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