|
Within a protein, a structural domain ("domain") is an element of overall structure that is self-stabilizing and often folds independently of the rest of the protein chain. Many domains are not unique to the protein products of one gene or one gene family but instead appear in a variety of proteins. Domains often are named and singled out because they figure prominently in the biological function of the protein they belong to; for example, the "calcium-binding domain of calmodulin. Because they are self-stabilizing, domains can be "swapped" by genetic engineering between one protein and another to make chimeras. A domain may be composed of one, more than one or not any structural motifs. A representation of the 3D structure of myoglobin, showing coloured alpha helices. ...
In biochemistry, the tertiary structure of a protein is its overall shape. ...
Protein folding is the process by which a protein assumes its functional shape or conformation. ...
This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ...
A gene family is a set of genes defined by presumed homology, i. ...
Calmodulin 3D structure Calmodulin (CaM) is a Ca2+-binding protein that is a key component of the Ca2+ second_messenger system and is involved in controlling many of the biochemical processes of cells. ...
An iconic image of genetic engineering; this 1986 autoluminograph of a glowing transgenic tobacco plant bearing the luciferase gene of fireflys strikingly demonstrates the power and potential of genetic manipulation. ...
A Chimera (or chimeric protein) is a human-engineered protein that is encoded by a nucleotide sequence made by a splicing together of two or more complete or partial genes. ...
In an unbranched, chain-like biological molecule, such as a protein or a strand of RNA, a structural motif is a three-dimensional structural element or fold within the chain, which appears also in a variety of other molecules. ...
An important tool in the determination of domains is structural alignment and sequence alignment. Protein structural alignment is a form of alignment which tries to establish equivalences between two or more protein structures based on their fold. ...
Sequence alignment is an arrangement of two or more sequences, highlighting their similarity. ...
Examples of protein structural domains
- Phosphotyrosine-binding domain (PTB). PTB domains usually bind to phosphorylated tyrosine residues. They are often found in signal transduction proteins. PTB-domain binding specificity is determined by residues to the amino-terminal side of the phosphotyrosine. Examples: the PTB domains of both SHC and IRS-1 bind to a NPXpY sequence. PTB-containing proteins such as SHC and IRS-1 are important for insulin responses of human cells.
- Pleckstrin homology domain (PH). PH domains bind phosphoinositides (PIP2 and PIP3) with high affinity. Given the fact that phosphoinositides are sequestered to the cell membrane due to their long lipophilic tail, the PH domain usually causes localization of the protein in question to the cell membrane, which is useful for expediting activation of the protein and continuation of a signaling pathway.
- Src homology 2 domain (SH2). SH2 domains are often found in signal transduction proteins. SH2 domains confer binding to phosphorylated tyrosine (pTyr). Named after the phosphotyrosine binding domain of the src viral oncogene, which is itself a tyrosine kinase. See also: SH3 domain.
- Cadherin repeats. Cadherins function as Ca2+-dependent cell-cell adhesion proteins. Cadherin domains are extracellular regions which mediate cell-to-cell homophilic binding between cadherins on the surface of adjacent cells.
- Armadillo repeats. Named after the β-catenin-like Armadillo protein of the fruit fly Drosophila. These domains are about 40 amino acids long and proteins that contain them often have many tandemly repeated domains. β-catenin is a protein involved in linking cadherin cell adhesion proteins to the cytoskeleton. This type of protein domain is important in transducing WNT signals during embryonic development.
- Zinc finger DNA binding domain (ZnF_GATA). ZnF_GATA domain-containing proteins are typically transcription factors that usually bind to the DNA sequence [AT]GATA[AG] of promoters.
- Death effector domain (DED). DED allows protein-protein binding by homotypic interactions (DED-DED). Caspase proteases trigger apoptosis via proteolytic cascades. Caspase-8 and caspase-9 bind to specific adaptor molecules via DED domains and this leads to autoactivation of caspases.
See also: structural biology The structure of insulin Red: carbon; green: oxygen; blue: nitrogen; pink: sulfur. ...
In structural biology, SHC, or Src homology 2 domain-containing, is a structural domain in signal transduction proteins. ...
An oncogene is a gene that can cause a cell to develop into a tumor cell, possibly resulting in cancer. ...
Tyrosine kinases are a subclass of protein kinase, see there for the principles of protein phosphorylation A tyrosine kinase (EC 2. ...
An SH3 domain is a protein module, a characteristic peptide sequence. ...
Schematic of cell adhesion The study of cell adhesion is part of cell biology. ...
Binomial name Drosophila melanogaster Meigen, 1830 Drosophila melanogaster (Black-bellied Dew-lover) a dipteran (two-winged) insect, is the species of fruit fly that is commonly used in genetic experiments; it is among the most important model organisms. ...
The cytoskeleton is a cellular scaffolding or skeleton contained, as all other organelles, within the cytoplasm. ...
Developmental biology is the study of the process by which organisms grow and develop. ...
A zinc finger is part of a protein that can bind to DNA. Zinc finger domains typically consist of two β sheets, each carrying a cysteine residue, and an α helix carrying two histidine residues. ...
In molecular biology, a transcription factor is a protein that binds DNA at a specific promoter or enhancer region or site, where it regulates transcription. ...
for disambiguation of the term promoter, see the promoter Wiktionary article In genetics, a promoter is a DNA sequence that enables a gene to be transcribed. ...
Caspases are a group of cysteine proteases, enzymes with a crucial cysteine residue that can cleave other proteins, after an aspartic acid residue, a specificity which is unusual among proteases. ...
Peptidases (proteases [pronounced pro-tea-aces] and proteolytic enzymes are also commonly used) are enzymes which break peptide bonds of proteins. ...
In biology, apoptosis (from the Greek words apo = from and ptosis = falling, pronounced ap-a-tow-sis[1]) is one of the main types of programmed cell death (PCD). ...
Structural biology is the study of the architecture and shape of biological macromolecules--proteins and nucleic acids in particular--and what causes them to have the structures they have. ...
External links |
Feeds |
Contact