A protein microarray, sometimes referred to as a protein binding microarray, is a piece of glass on which different molecules of
proteinhave been affixed at separate locations in an ordered manner thus forming a microscopic array. These are used to identify protein-protein interactions, to identify the substrates of protein kinases, or to identify the targets of biologically active small molecules. The most common protein microarray is the antibody microarray, where antibodies are spotted onto the protein chip and are used as "capture molecules" to detect proteins from cell lysatesolutions.
Related microarray technologies also include
DNA microarrays, cellular microarrays, antibody microarrays, tissue microarrays and chemical compound microarrays.
Protein microarrays (also biochip, proteinchip) are measurement devices used in biomedical applications to determine the presence and/or amount (referred to as quantitation) of proteins in biological samples, e.g.
blood. They have the potential to be an important tool for proteomicsresearch. Usually a multitude of different capture agents, most frequently monoclonal antibodies, are deposited on a chip surface (glass or silicon) in a miniature array. This format is often also referred to as a microarray (a more general term for chip based biological measurement devices).
Types of chips
There are several types of protein chips, the most common being glass slide chips and nano-well arrays.
Production of protein arrays
The proteins can be externally synthesised, purified and attached to the array. Alternatively they can be synthesised in-situ and directly attached to the array.
The proteins can be synthesised through biosynthesis, cell-free DNA expression or chemical synthesis. In-situ synthesis is possible with the latter two. With cell-free DNA expression, proteins are attached to the support right after their production. Peptides chemically procured by solid phase peptide synthesis are already attached to the support. Selective deprotection is carried out through lithographic methods or by the so-called SPOT-synthesis.
Artifacts to avoid
*1) To avoid variability in results, use a very efficient lysis buffer and maintain consistent sample processing conditions;
*2) Many antibodies don't work well as capture reagents, even if they do work well in western blotting and other denaturing conditions. Some antibodies often bind poorly to intact proteins in a cell extract;
*3) Different proteins like different solution conditions, so if you do not see binding it doesn't mean that there is no binding between the two partners in physiological conditions;
*4) Adjust the solute conditions to avoid non-specific association: change salt concentration, pH, add 1% alignate;
*5) on the array's surface the conjugated protein should be in the right conformation (i.e., folded, NOT denatured), anchored by the same amino acid (in the same orientation), and be kept away from the surface by a linker to avoid steric hindrance.
Types of capture molecules
Capture molecules used are most commonly
antibodies; however, antigens are used in applications where antibodies are detected in serum. More recently there has been a push towards other types of capture molecules which are more similar in their nature such as peptides or aptamers. Antibodies have several problems including the fact that there are not antibodies for most proteins and also problems with specificity in some commercial antibody preparations. Nevertheless, antibodies still represent the most well-characterized and effective protein capture agent for microarrays. Recently, nucleic acids, receptors, enzymes, and proteins have been spotted onto chips and used as capture molecules. This allows a vast variety of experiments to be conducted on protein-protein interactions, and all other protein binding substrates.
Although protein microarrays may use similar detection methods as DNA Microarrays, a problem is that protein concentrations in a biological sample may be many orders of magnitude different from that for mRNAs. Therefore, protein chip detection methods must have a much larger range of detection.
The preferred method of detection currently is
fluorescencedetection. Fluorescent detection is safe, sensitive, and can have a high resolution. The fluorescent detection method is compatible with standard microarray scanners, however some minor alterations to software may need to be made. Other common detection methods include colorimetric, chemiluminescent and label free Surface Plasmon Resonance.
Chemical compound microarray
MicroArray and Gene Expression(MAGE)
* Gavin MacBeath and
Stuart L. Schreiber(8 September 2000) [http://www.sciencemag.org/cgi/content/abstract/289/5485/1760 "Printing Proteins as Microarrays for High-Throughput Function Determination"] . Science 289 (5485), 1760–1763
* Richard B. Jones, Andrew Gordus, Jordan A. Krall, and Gavin MacBeath (12 January 2006) [http://www.nature.com/nature/journal/v439/n7073/abs/nature04177.html "A quantitative protein interaction network for the ErbB receptors using protein microarrays"] . Nature 439, 168–174. This gives an example of the applied use of protein microarrays.
* Daniel S. Chen, Mark M. Davis MM (2006) Molecular and functional analysis using live cell microarrays. Curr Opin Chem Biol 10:28–34
* [http://www.innobiochips.fr Custom peptides and proteins microarrays]
* [http://www.vega.org.uk/video/programme/70 'Self Assembly Nature's Way to Do It'] Freeview Video of a Royal Institution Discourse by Kuniaki Nagayama, Toyko University supplied by the Vega Science Trust.
* [http://bioscience.jbpub.com/catalog/0763731277/table_of_contents.htm Principles of Protein Microarrays; Mark Schena]
* [http://www.clinchem.org/cgi/content/full/48/1/121 Antigen Microarrays for Serodiagnosis of Infectious Diseases]
* [http://chp.rcsi.ie/research/ Biomarker Discovery using Protein Arrays]
* [http://pubs.acs.org/subscribe/journals/ancham/79/i23/pdf/1207feature_griffiths.pdf Feature article about protein microarrays] from [http://pubs3.acs.org/acs/journals/toc.page?incoden=ancham&indecade=0&involume=79&inissue=23 the December 1, 2007 issue of "Analytical Chemistry"]
* [http://www.cshprotocols.org/cgi/content/full/2007/6/pdb.top2 Assays with Protein Arrays]
Wikimedia Foundation. 2010.
Look at other dictionaries:
MicroArray — ist eine Sammelbezeichnung für moderne molekularbiologische Untersuchungssysteme, die die parallele Analyse von mehreren tausend Einzelnachweisen in einer geringen Menge biologischen Probenmaterials erlauben. Es gibt verschiedene Formen von… … Deutsch Wikipedia
Microarray — ist eine Sammelbezeichnung für moderne molekularbiologische Untersuchungssysteme, die die parallele Analyse von mehreren tausend Einzelnachweisen in einer geringen Menge biologischen Probenmaterials erlauben. Es gibt verschiedene Formen von… … Deutsch Wikipedia
Protein (disambiguation) — Protein is a class of biomolecules composed of amino acid chains.Protein may also refer to:Biochemistry* Antifreeze protein, class of polypeptides produced by certain fish, vertebrates, plants, fungi and bacteria * Conjugated protein, protein… … Wikipedia
Protein-protein interaction prediction — is a field combining bioinformatics and structural biology in an attempt to identify and catalog interactions between pairs or groups of proteins. Understanding protein protein interactions is important in investigating intracellular signaling… … Wikipedia
Protein — Proteins are large organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid residues. The sequence of amino acids in a protein is defined by … Wikipedia
Protein-Chip — Der Protein Chip oder Protein Microarray ist ein vielversprechendes proteomisches Werkzeug in der klinischen Diagnostik, molekularbiologischen Forschung sowie der Lebensmittel und Umweltanalytik. Eine verwandte Methode ist der DNA Chip.… … Deutsch Wikipedia
Microarray analysis techniques — Example of an approximately 40,000 probe spotted oligo microarray with enlarged inset to show detail. Microarray analysis techniques are used in interpreting the data generated from experiments on DNA, RNA, and protein microarrays, which allow… … Wikipedia
Protein isoform — A protein isoform is a version of a protein with only small differences to another isoform of the same protein. [http://en.wiktionary.org/wiki/isoform] Different forms of a protein may be produced from different but related genes, or may arise… … Wikipedia
Microarray — A microarray is a multiplex lab on a chip. It is a 2D array on a solid substrate (usually a glass slide or silicon thin film cell) that assays large amounts of biological material using high throughput screening methods. Types of microarrays… … Wikipedia
microarray — mi·cro·ar·ray ə rā n a supporting material (as a glass or plastic slide) onto which numerous molecules or molecular fragments usu. of DNA or protein are attached in a regular pattern for use in biochemical or genetic analysis esp DNA microarray * … Medical dictionary