Proteasome
Proteasomes are large protein complexes inside all eukaryotes and archaea, as well as in some bacteria. In eukaryotes, they are located in the nucleus and the cytoplasm.The main function of the proteasome is to degrade unneeded or damaged proteins by proteolysis, a chemical reaction that breaks peptide bonds. Enzymes that carry out such reactions are called proteases. Proteasomes are a major mechanism by which cells regulate the concentration of particular proteins and degrade misfolded proteins. The degradation process yields peptides of about seven to eight amino acids long, which can then be further degraded into amino acids and used in synthesizing new proteins.Proteins are tagged for degradation by a small protein called ubiquitin. The tagging reaction is catalyzed by enzymes called ubiquitin ligases. Once a protein is tagged with a single ubiquitin molecule, this is a signal to other ligases to attach additional ubiquitin molecules. The result is a polyubiquitin chain that is bound by the proteasome, allowing it to degrade the tagged protein.
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proteasome
Added: August 20, 2007, 2:44 am
Runtime: 44.50 | Views: 7232 |
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Fatal Familial Insomnia Point Mutation
A simple animation showing the mutation of a single nucleotide on codon 178 PrP gene which causes a change in the encoded amino acid from aspartic acid to asparagine.
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Insomnia
Added: August 20, 2007, 5:58 pm
Runtime: 32.91 | Views: 6989 |
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Bone Marrow Transplantation Video
Fred Hutchinson Cancer Research Center bone marrow transplantation program, in partnership with the Seattle Cancer Care Alliance (SCCA), is the largest program in the world. Through basic and applied research, efforts are underway to expand transplantation options and to develop new leading-edge therapies. Our patients have access to some of the most advanced oncology therapies available anywhere in the world, along with world-class patient care, and unmatched social and family-support services.
Reff: http://www.fhcrc.org
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bonemarrow
Added: August 21, 2007, 6:38 pm
Runtime: 613.00 | Views: 9347 |
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What is HPE? How does the normal brain develop?
holoprosencephaly : A birth defect where the forebrain does not separate properly into two halves during early fetal life. The disorder results in mild to severe brain malformation and is sometimes fatal. It may be caused by environmental or genetic factors. Holoprosencephaly affects between 1 in 5,000 and 1 in 10,000 live births.
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holoprosencephaly
Added: August 21, 2007, 6:51 pm
Runtime: 108.11 | Views: 5199 |
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Lecture : Catalysis: Chemical and Biochemical by Thomas R. Cech, Ph.D. part 2
The Double Life of RNA The Lectures 1. Presented by HHMI investigator and Nobel laureate Thomas R. Cech, Ph.D. www.hhmi.org
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rnailecture
Added: August 31, 2007, 7:35 pm
Runtime: 378.14 | Views: 3422 |
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