Algae, Tree, Herbs, Bush, Shrub, Grasses, Vines, Fern, Moss, Spermatophyta, Bryophyta, Fern Ally, Flower, Photosynthesis, Eukaryote, Prokaryote, carbohydrate, vitamins, amino acids, botany, lipids, proteins, cell, cell wall, biotechnology, metabolities, enzymes, agriculture, horticulture, agronomy, bryology, plaleobotany, phytochemistry, enthnobotany, anatomy, ecology, plant breeding, ecology, genetics, chlorophyll, chloroplast, gymnosperms, sporophytes, spores, seed, pollination, pollen, agriculture, horticulture, taxanomy, fungi, molecular biology, biochemistry, bioinfomatics, microbiology, fertilizers, insecticides, pesticides, herbicides, plant growth regulators, medicinal plants, herbal medicines, chemistry, cytogenetics, bryology, ethnobotany, plant pathology, methodolgy, research institutes, scientific journals, companies, farmer, scientists, plant nutrition
Select Language:
 
   
 
 
Can't find? Try Deep Search with ePlantScience.com  
 
Share |
 
   
Main Menu
If navigation gets difficult, please click the main subject or sitemap to get the list of sub-categories
 
 
 
 
 
Related websites
 
 
 
 
 
 
 
 
Section: Genetics » Expression of Gene » Translation in Prokaryotes and Eukaryotes
 
 
If you like this page, please click:  
 
 
  Termination of polypeptide
 
     
 
Content
⇒ Expression of Gene : Protein Synthesis 4. Translation in Prokaryotes and Eukaryotes
⇒ Formation of amino-acyl tRNA
⇒ Initiation of polypeptide 
⇒ Initiation in prokaryotes
⇒ Initiation in eukaryotes
⇒ Kozak's scanning hypothesis
⇒ Elongation of polypeptide
⇒ Binding of AA-tRNA at site 'A' of ribosome
⇒ Formation of peptide bond
⇒ Translocation of peptidyl tRNA from 'A' to 'P' site
⇒ Termination of polypeptide
⇒ Modification, folding and transport of released polypeptide
⇒ Translation in chloroplasts and mitochondria
Termination of Polypeptide
Termination of the polypeptide chain is brought about by the presence of any one of the three termination codons, namely UAA, UAG and UGA (consult The Genetic Code). These termination codons are recognized by one of the two release factors RF1 and RF2. Of these release factors, RF1 recognizes UAA and UAG and RF2 recognizes UGA. They help the ribosome to recognize these triplets. The release factors seem to act on 'A' site, since suppressor tRNA capable of recognizing termination codons can compete with release factors by entry at 'A' site. A third release factor RF3 seems to stimulate the action of RF1 and RF2. For release reaction, the polypeptidyl tRNA must be present on 'P' site and the release factors help in splitting of the carboxyl group between the polypeptide and the last tRNA carrying this chain. Polypeptide is thus released and the ribosome dissociates into two subunits with the help of IF-3.

In eukaryotic system only one release factor is known i.e. eRFI. GTP seems to be necessary for binding of this factor to ribosome. GTP is cleaved after the termination step has occurred which may be a prerequisite for the release of eRFI from the ribosome.

 
     






     
     
 
 
     
 
Copyrights 2009 © ePlantScience.com