termination

Examples of termination in the following topics:

• DNA Sequencing Based on Sanger Dideoxynucleotides

  • The classical chain-termination method requires a single-stranded DNA template, a DNA primer, a DNA polymerase, normal deoxynucleotidetriphosphates (dNTPs), and modified nucleotides (dideoxyNTPs) that terminate DNA strand elongation .
  • Chain-termination methods have greatly simplified DNA sequencing.
  • More recently, dye-terminator sequencing has been developed.
  • Dye-terminator sequencing utilizes labelling of the chain terminator ddNTPs, which permits sequencing in a single reaction, rather than four reactions as in the labelled-primer method.
  • In dye-terminator sequencing, each of the four dideoxynucleotide chain terminators is labelled with fluorescent dyes, each of which emit light at different wavelengths .

• Attenuation

  • The process of attenuation involves the presence of a stop signal that indicates premature termination.
  • Transcription-attenuation is characterized by the presence of 5'-cis acting regulatory regions that fold into alternative RNA structures which can terminate transcription.
  • These RNA structures dictate whether transcription will proceed successfully or be terminated early, specifically, by causing transcription-attenuation.
  • The result is a misfolded RNA structure where the Rho-independent terminator disrupts transcription and produced a non-functional RNA product.
  • The other RNA structure produced will be an anti-terminator that allows transcription to proceed .

• Regulation by Biosynthetic Enzymes

  • Attenuation is a regulatory feature found throughout Archaea and Bacteria domains which causes premature termination of transcription.
  • Attenuation is a regulatory feature found throughout Archaea and Bacteria causing premature termination of transcription.
  • The folding is modulated by a sensing mechanism producing either a Rho-independent terminator, resulting in interrupted transcription and a non-functional RNA product; or an anti-terminator structure, resulting in a functional RNA transcript.
  • Attenuator is a nucleotide sequence in DNA that can lead to premature termination of transcription.
  • Since the protein coding genes are not transcribed due to rho independent termination, no tryptophan is synthesized.

• Prokaryotic Transcription and Translation Are Coupled

  • The -35 region and the -10 ("Pribnow box") region comprise the basic prokaryotic promoter, and |T| stands for the terminator.
  • The DNA on the template strand between the +1 site and the terminator is transcribed into RNA, which is then translated into protein.
  • Two termination mechanisms are well known: Intrinsic termination (also called Rho-independent transcription termination) involves terminator sequences within the RNA that signal the RNA polymerase to stop.
  • Rho-dependent termination uses a termination factor called ρ factor(rho factor) which is a protein to stop RNA synthesis at specific sites.
  • A stem loop structure upstream of the terminator region pauses the RNAP, when ρ-factor reaches the RNAP, it causes RNAP to dissociate from the DNA, terminating transcription.

• Electron Donors and Acceptors in Anaerobic Respiration

  • In anaerobic respiration, a molecule other than oxygen is used as the terminal electron acceptor in the electron transport chain.
  • This method still incorporates the respiratory electron transport chain, but without using oxygen as the terminal electron acceptor .
  • Denitrification is the utilization of nitrate (NO3−) as the terminal electron acceptor.
  • Ferric iron (Fe3+) is a widespread anaerobic terminal electron acceptor used by both autotrophic and heterotrophic organisms.
  • A molecule other than oxygen is used as the terminal electron acceptor in anaerobic respiration.

• 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.
  • The phosphoryl group is then shuttled to histidine phosphotransferase (HPT) and subsequently to a terminal RR, which can evoke the desired response.
  • Histidine kinases usually have an N-terminal ligand-binding domain and a C-terminal kinase domain, but other domains may also be present.
  • Most orthodox HKs, typified by the Escherichia coli EnvZ protein, function as periplasmic membrane receptors and have a signal peptide and transmembrane segment(s) that separate the protein into a periplasmic N-terminal sensing domain and a highly conserved cytoplasmic C-terminal kinase core.
  • The blades are formed by two N-terminal domains each, and the compact central hub assembles the C-terminal kinase domains.

• Scarlet Fever

  • A transcriptional terminator is located 69 bases downstream from the translational termination codon.
  • The carboxy terminal portion of the protein exhibits extensive homology with the carboxy terminus of Staphylococcus aureus enterotoxins B and C1.

• Iron Oxidation

  • Ferric iron is an anaerobic terminal electron acceptor, with the final enzyme a ferric iron reductase.
  • Ferric iron (Fe3+) is a widespread anaerobic terminal electron acceptor both for autotrophic and heterotrophic organisms.

• Paralysis-Causing Bacterial Neurotoxins

  • The heavy chain of the toxin is particularly important for targeting the toxin to specific types of axon terminals.
  • The toxin must get inside the axon terminals to cause paralysis.
  • Following the attachment of the toxin heavy chain to proteins on the surface of axon terminals, the toxin can be taken into neurons by endocytosis.

• Syntrophy and Methanogenesis

  • In methanogenesis, carbon is used as the terminal electron receptor instead of oxygen.
  • Although there are a variety of potential carbon based compounds that are used as electron receptors, the two best described pathways involve the use of carbon dioxide and acetic acid as terminal electron acceptors.