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./Jack

Predict domain strucutre by amu and percentage of secondary structure

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./Jack    0

Hello everybody,

I'm doing my biochemistry exam review and stumbled upon a question from last years exam, I really can't get anything out of google.
The question goes as follows:

Quote

 

The two 10 kDa domains of γ-crystallin contain mostly (>90%) β-sheet secondary structure. Each domain will most likely be comprised of:

A. A single β-sheet of parallel β-strands connected by β-turns (reverse turns).
B. Two β-sheets made of parallel β-strands connected by short helices.
C. Two β-sheets made up of antiparallel β-strands.
D. A single β-sheet of antiparallel β-strands, so the two domains can pack against each other.

 

Correct is answer C. However, I can't quite figure out why. My reasoning so far:

-> If the Beta strands were connected by (short) alpha helices, the protein wouldn't be 90% Beta sheets, so B is out.

-> I've never heard of domains packing against each other, and since they fold independently, I don't think this is right.

But this is both rather washy reasoning. I can't figure out what information the "two 10 kDa domains" is supposed to give me.

 

Thank you for your time and any tips :)

Jack

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Vmedvil    8
3 hours ago, ./Jack said:

Hello everybody,

I'm doing my biochemistry exam review and stumbled upon a question from last years exam, I really can't get anything out of google.
The question goes as follows:

Correct is answer C. However, I can't quite figure out why. My reasoning so far:

-> If the Beta strands were connected by (short) alpha helices, the protein wouldn't be 90% Beta sheets, so B is out.

-> I've never heard of domains packing against each other, and since they fold independently, I don't think this is right.

But this is both rather washy reasoning. I can't figure out what information the "two 10 kDa domains" is supposed to give me.

 

Thank you for your time and any tips :)

Jack

Here is what two anti parallel DNA would look like does it look like that?

dsDNA.jpg

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BabcockHall    37

A is not a reasonable answer, either.  Antiparallel strands can be connected by beta-turns, but I don't see how parallel strands could be.  As a generalization, I don't see why domains cannot pack against each other.  However, I think that answer D is internally inconsistent.  See what you can do with that.

Edited by BabcockHall

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