When and Where do Proteins Fold?

[iain399]

The answer should be, "we don't know". Fair enough, thanks

[TheGrotesqueReality]

Q: what kind of RNA translates to protein? A:1

Q: what sort of bonds bind amino acids in a protein? A:2

Q: where a protein gets folded? A:4

Q: why does the chicken cross the road? A:6

Q: doesn’t this protein look funny? A:9

[duguder]

Please not 240p?

[beatthegypsy]

when and where do proteins fold?

.... we dont really know...?

[mudyar]

Twiddling of thumbs very distracting.

[wkdzairi]

FAIL....mRNA gets TRANSLATED at ribosomes not transcribed.

after he said that i just stopped watching.

[ipodvidoe]

@wkdzairi I'm sure it was just a verbal mistake. I'm PRETTY sure he knows the difference.

[thechessstick]

Wow! What an awesome design. It is beyond the mind of man.

[tim0090]

@thechessstick

for now maybe!!!

[OurNewestMember]

transcription does not equal polypeptide synthesis. :-(

[livintzitu]

proteins ar chains... long thin chains. and they are not folded in the reticulum, but their sequence of aminoacids is what determins where they fold. that is why the sequence is important, as the function of the protein is determined by it's shape

[aabaruff]

Protein Folding occurs in the Endoplasmic Reticulum. it is nicknamed the "Protein Folding Factory" , but I'm sure that there's more to learn. I'm surprised he didn't mention ER once.

[dls3189]

what does it mean by folding a protein?

[sirpolopaul]

I am interested in what helps the chaperones or chaperonins fold. Could it be another chaperone? If it is, could we propose a cycle for these biochemical reactions?

[maciejwrotek]

Is it possible that protein is folded in the exact moment when it leaves the exit of the ribosome ? Why should protein wait to be translated fully, and then start to fold ?

[sirpolopaul]

Q1:Yeah it is possible.

Q2:WHAT determine the folding of protein is mainly its primary sequences of residues, so the protein has to be translated fully, in order to fold correctly(not starting to fold, the protein chain may start to twist when it is being translated).

[maciejwrotek]

Hmmmm... Protein chain twists while being translated, just after it leaves the exit of the ribosome(many nice videos of it on youtube). I suggest the folding process is an "amino acid after amino acid " sequence, just like translation, folding is a step by step . That is why it is fast, but i don't know if computer simulations include this idea.

Next thing i was wondering about, a ribosome is a protein, what makes this protein ? Another ribosome ? (Oo,) What is first, chicken or ann egg.

[sirpolopaul]

I cannot quite understand your "amino acid after amino acid " sequence theory. Protein may fold by the hydrophobicity of the amino acids, hydrogen bond, interaction with the surrounding, Molecular Chaperone etc.That's why the hydrophobic residues are aways inside the interior of the protein and the hydrophilic residues are usually at the exterior where they are in contact with the aqueous surroundings. So folding is not from one amino acid to another amino acid. The protein folds as a whole.

[maciejwrotek]

Hmmm i think U understand pretty well my theory.

But from the other point of view, if protein folded on the exit, there would be no point for ER and golgi aparatus to exist, and as You mention the chaperones too.

So u say that robosome exist from the beginning of the embryo ? Hmmm....

So they must come from the parent organism.

[planetinvader]

Hmmm folding is not primarily due to primarily and secondary structures, it is even controlled by the tertiary structures. Please read on the 3 hypotheses for the mechanism of Folding. 1. Hierarchical, 2. Nucleation-condensation, 3. Hydrophobic Collapse. What you are suggesting above does not hold true. Read about the 3 above hypotheses. Good luck!

[sirpolopaul]

I agree that primary stucture(which is the amino acid sequence of the petide) might not be determinant in the comformation of protein. But it is still important in folding process. Just to mention the hydrophobic collapse model. It suggests the core of globular protein as hydrophotic with non-polar residues while the extorior is hydrophilic with polar ones. Therefore the property of the side chain of amino acid do determine the final folds of the protein, the same as I suggested.

[planetinvader]

That is true. Guess what, I have a Biochem exam Wednesday. HHahahah advance Biochem graduate school.

[sirpolopaul]

Ribosomes are splitted into 2 subunits, while each subunite is joined by several polypeptide chains and RNA molecules. Those polypeptide chains are transcripted by ribosomes. It is a cycle, both of them exist when you are still a developing embryo.

And the videos you are suggesting are not reflection of the reality. so far our microscope cannot have the resolution to see a molecule. And the time for one translation is very fast, it is difficult to "freeze" the molecule for NMR or x-ray crystal.

[planetinvader]

Complete folding is when the protein is in active form. Sometimes holding the protein one step to folding completion can be helpful, those proteins are held until needed. Chaperons like Trigger Factor and Hsp70 are holding proteins. Read on Chaperons like Hsp60, Hsp70, 90, 100, Trigger Factor, NAC etc...