A protein domain is a conserved part of a given protein sequence and structure that can evolve, function, and exist independently of the rest of the protein chain. Each domain forms a compact three-dimensional structure and often can be independently stable and folded. Many proteins consist of several structural domains. One domain may appear in a variety of different proteins. Molecular evolution uses domains as building blocks and these may be recombined in different arrangements to create proteins with different functions. Domains vary in length from between about 25 amino acids up to 500 amino acids in length. The shortest domains such as zinc fingers are stabilized by metal ions or disulfide bridges. Domains often form functional units, such as the calcium-binding EF hand domain of calmodulin. Because they are independently stable, domains can be "swapped" by genetic engineering between one protein and another to make chimeric proteins.
Read more about Protein Domains: Background, Domains Are Units of Protein Structure, Domains As Evolutionary Modules, Multidomain Proteins, Domains and Protein Flexibility, Domain Definition From Structural Co-ordinates, See Also, References
... The source of protein structures is the Protein Data Bank ... The unit of classification of structure in SCOP is the protein domain ... What the SCOP authors mean by "domain" is suggested by their statement that small proteins and most medium sized ones have just one domain, and by the observation that human hemoglobin ...
... The syndecan proteins can contain the following protein domains, A signal sequence An extracellular domain (ectodomain) of variable length whose sequence is not evolutionary conserved in the various ... chains A transmembrane region A highly conserved cytoplasmic domain of about 30 to 35 residues, which could interact with cytoskeletal proteins ...
... (2002) "Predicting Structural Domains in Proteins" Thesis, University College London, which were contributed by its author ...
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