mildus wrote:
The question was about how ubiquitin knows which protein is damaged and needs to be degradated.
I was just curious to find out. I don't know if it is importnat for USMLE, if it isn't, then forget it.
I found out that ubiquitin recognizes some structural features of the damaged protein (so called "degradation signals" or DEGRONS)
Hey just to add on to what you said, proteins emerge from ribosomes as a straight line. Then they are usually folded in the RER --> The FOLDING of that protein determines the function and capacity of that protein.
There are 4 levels of protein shape (as the shape advances in structure you have more folding taking place)
1. Primary structure = just a sequence of AAs
2. Secondary structure = alpha-helix and beta-pleated sheat
3. Tertiary structure = Hb subunit
4. Quaternary structure = multi-subunit protein (HbA)
Your question was how does the cell know which proteins to mark with ubiquitin?
If the protein is MISFOLDED for whatever reason, the cell will mark it with Ubiquitin, and once marked it will be sent to the Proteosome for degradation.
The only questions I had so far on all this was -- (1) what proteins assist in the process of protein folding (2) Something about Ubiquitin (3) They described an example of a quaternary structure and then asked what largely maintains or holds these structures together.
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| msyamp
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here is somethings on protein folding
chaperones are the protiens heping folding.
chaperones can be normally synthsised or synth during stress.
stress chaperones rescue proteins from abnormal foling
if the protein could not be rescued it is given awat for ubiqutin which binds and facilitates its degradation.
diseases associated with abnormal protein folding are?
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