domain

Examples of domain in the following topics:

• Two-Component Regulatory Systems

  • The N-terminal domain of this protein forms part of the cytoplasmic region of the protein, which may be the sensor domain responsible for sensing turgor pressure.
  • Histidine kinases usually have an N-terminal ligand-binding domain and a C-terminal kinase domain, but other domains may also be present.
  • Members of this family, however, have an integral membrane sensor domain.
  • In addition to the sensor domain and kinase core, they contain a CheY-like receiver domain and a His-containing phosphotransfer (HPt) domain.
  • The blades are formed by two N-terminal domains each, and the compact central hub assembles the C-terminal kinase domains.

• Regulation by Biosynthetic Enzymes

  • (This differs from eukaryotic cells, where RNA must exit the nucleus before translation starts. ) The attenuator sequence, which is located between the mRNA leader sequence (5' UTR) and trp operon gene sequence, contains four domains, where domain 3 can pair with domain 2 or domain 4.
  • A high level of tryptophan will permit ribosomes to translate the attenuator sequence domains 1 and 2, allowing domains 3 and 4 to form a hairpin structure, which results in termination of transcription of the trp operon.
  • In contrast, a low level of tryptophan means that the ribosome will stall at domain 1, causing the domains 2 and 3 to form a different hairpin structure that does not signal termination of transcription.
  • Thus, domain 4 is an attenuator.
  • Without domain 4, translation can continue regardless of the level of tryptophan.

• Mapping Protein-Protein Interactions

  • Molecular studies are necessary to dissect the constituents of these protein complexes and identify the domains through which a protein interacts with another.
  • The method consists of splitting a yeast transcription factor into its binding domain and activation domain, fusing the binding domain to one protein of interest (the bait) and the activation domain to another protein of interest (the prey), and reconstituting the activity of the transcription factor by bringing the two domains back into physical proximity.
  • In the absence of an interaction the domains remain distant, preventing a detectable output.

• The Taxonomic Scheme

  • These ranks range in ascending scale from family to suborder, and upward to order, subclass, class, division/phyla, kingdom and domain.
  • In the currently accepted scientific classification of Life, there are three domains of microorganisms: the Eukaryotes, Bacteria and Archaea, The different disciplines of study refer to them using differing terms to speak of aspects of these domains, however, though they follow similar principles.
  • Thus botany, zoology, mycology, and microbiology use several different conventions when discussing these domains and their subdivisions.
  • Thus, though Woese identified three primary lines of descent the Archaebacteria, the Eubacteria and the Urkaryotes, the latter now represented by the nucleocytoplasmic component of the Eukaryotes. these lineages were formalised into the rank Domain (regio in Latin) which divided Life into 3 domains: the Eukaryota, the Archaea and the Bacteria.

• Two-Hybrid Analysis

  • The method consists of splitting a yeast transcription factor into its binding domain and activation domain, fusing the binding domain to one protein of interest (the bait) and the activation domain to another protein of interest (the prey), and reconstituting the activity of the transcription factor by bringing the two domains back into physical proximity.
  • In the absence of an interaction the domains remain distant, preventing a detectable output.

• Historical Overview of Eukaryotes

  • The disentanglement of the deep splits in the tree of life only really got going with DNA sequencing, leading to a system of domains rather than kingdoms as top level rank being put forward by Carl Woese, uniting all the eukaryote kingdoms under the eukaryote domain .
  • As such the tree of life consists of three domains: Archaea, Bacteria, and Eukarya.

• Classification of Microorganisms

  • The first, largest, and most inclusive group under which organisms are classified is called a domain and has three subgroups: bacteria, archae, and eukarya.
  • The domain was proposed by the microbiologist and physicist Carl Woese in 1978 and is based on identifying similarities in ribosomal RNA sequences of microorganisms.
  • Domain: Bacteria, Kingdom: Eubacteria, Phylum: Proteobacteria, Class: Gammaproteobacteria, Order: Enterobacteriales, Family: Enterobacteriaceae, Genus: Escherichia, Species: E. coli.

• T Cell Receptors

  • Each alpha and beta chain consists of one variable domain (V), one constant domain (C), a hydrophobic transmembrane region, and a short cytoplasmic region .
  • T cell receptor consists of alpha and beta chains, a transmembrane domain, and a cytoplasmic region.

• Common Bacterial Traits

  • Bacteria constitute a large domain of prokaryotic microorganisms.
  • However, molecular systematics show prokaryotic life to consist of two separate domains, originally called Eubacteria and Archaebacteria, but now called Bacteria and Archaea that evolved independently from an ancient common ancestor .
  • Phylogenetic tree showing the relationship between the Archaea and other domains of life.

• Growth Rate and Temperature

  • For example, in molecular biology, the cold-shock domain (CSD) is a protein domain of about 70 amino acids which has been found in prokaryotic and eukaryotic DNA-binding proteins.
  • Part of this domain is highly similar to the RNP-1 RNA-binding motif.
  • During the lag phase, the expression of around 13 proteins, which contain cold shock domains is increased two- to ten-fold.