The video makes the abstract concept a little easier. But I still have no idea of what is the supercoil. I even have difficulty understanding why the telephone line wind together.
A. Right handed supercoiling = negative supercoiling (underwinding) B. Left handed supercoiling = positive supercoiling www.siumed.edu/~bbartholomew/-lectures/Supercoiling.pdf
Isn't it TOPO I who introduces supercoiling while the II relaxes them? can you please recheck if the info in the video is actually in the opposite term? tqsm
Both of them relaxes, topo 1 acts only on one strand while topo 2 acts on both strands of dna. And the supercoiling is due to unwinding of dna (enz- helicase).
It is the dna gyrase ,a type 2 topoisomerase, that introduces negative supercoils to neutralize the positive supercoils, in bacteria and plants ,but the aim is to uncoil.
I'm confused. first you said that negative supercoiling is caused by DNA unwinding, but then you said that supercoiling can be relived by unwinding the DNA. Which one is it?
nevermind.. I think I got it but I'm not 100% sure. is it because negative supercoiling occurs when the DNA is relaxed, but when the DNA is supercoiled already the tension can be relieved by unwinding the DNA? could you confirm?
Negative supercoils are introduced into the bacterial chromosome by DNA gyrase. In the absence of topoisomerase I and topoisomerase IV, the DNA becomes hypernegatively supercoiled. The steady-state level of supercoiling in Escherichia coli is maintained by a balance between topoisomerase IV, acting in concert with topoisomerase I, to remove excess negative supercoils and thus acting in opposition to DNA gyrase.A typical bacterial chromosome contains approximately 50 giant loops of supercoiled DNA arranged around a protein scaffold. In Figure 4.16, the single line represents a double helix of DNA and the helixes are the supercoils.
"Type II topoisomerases (DNA Gyrase of E.coli). The gyrase enzyme grabs DNA and, in an ATP-dependent process, introduces a double-strand break, passes another part of the double helix through the break, and then reseals the break. The end result is the introduction of a negative supercoil" (Microbiology: An evolving science p 247)
Type I topoisomerases cleave only one strand of a double helix and are generally used to relieve or unwind supercoils. Type 1 enzymes are usually single proteins. (p247)
I come back to this video every time I forget anything about DNA supercoiling and it never fails me. Thank you!
Perfectly summarized my chapter. Thank you!!!
Love it, it made this concept really easy. Thanks!
The video makes the abstract concept a little easier. But I still have no idea of what is the supercoil. I even have difficulty understanding why the telephone line wind together.
Betty Chang studying for exams?
I had so much struggles about knowing tgis but finally this helped me.
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Wonderful video! This makes so much more sense than just reading it.
you have done god's work here. thank you
Beautiful explanation. thank you!
she is like seedhi baat no bakwas awesome video .... very helpful
Thank you for the amazing video
Perfect explanation,thank you
Great video👌so helpful
Very well explained ty!
thanks a lot! this is great!
awsome, thanks.
Excellent animation
Thanks, it was really helpful.
The best video on supercoiling on youtube! thanks
Thanked helped me out big time
Love this 😍😍😍😍😍😍😍
Why is DNA more difficult to replicate using positive supercoils yet they make the DNA loose?
A small inaccuracy: the ATPase of DNA Gyrase is GyrB not GyrA
Excellent
Note to self; use the animation of 2 kinds of topoisomeres for visualization
Thanks a lot nice explanation
Wow.. Thank u💙
amazing
Great and helpfull tnx alot
Thank u💛💛
buenisimo!☺
thanque so much love from india
My question is : what is the difference between positive and negative supercoiled ?
A. Right handed supercoiling = negative supercoiling (underwinding)
B. Left handed supercoiling = positive supercoiling
www.siumed.edu/~bbartholomew/-lectures/Supercoiling.pdf
RJ A
I was confused also.but this helped me to understand.
czcams.com/video/aD67gi6bXws/video.html
very well
Isn't it TOPO I who introduces supercoiling while the II relaxes them? can you please recheck if the info in the video is actually in the opposite term? tqsm
Both of them relaxes, topo 1 acts only on one strand while topo 2 acts on both strands of dna. And the supercoiling is due to unwinding of dna (enz- helicase).
It is the dna gyrase ,a type 2 topoisomerase, that introduces negative supercoils to neutralize the positive supercoils, in bacteria and plants ,but the aim is to uncoil.
I'm confused. first you said that negative supercoiling is caused by DNA unwinding, but then you said that supercoiling can be relived by unwinding the DNA. Which one is it?
nevermind.. I think I got it but I'm not 100% sure. is it because negative supercoiling occurs when the DNA is relaxed, but when the DNA is supercoiled already the tension can be relieved by unwinding the DNA? could you confirm?
I was also confused but this really helped me.
czcams.com/video/aD67gi6bXws/video.html
@@goofygoober6211 it really helps me to understand. czcams.com/video/aD67gi6bXws/video.html
Pie se maksute? Aku gapaham😢 artine
The animation is incorrect, top 1 doesnt create a separation of the two strands of the DNA
Ok....
This is fucking confusing
a lot of misinform
Please list your specific grievances so that I may try to address them
Negative supercoils are introduced into the bacterial chromosome by DNA gyrase.
In the absence of topoisomerase I and topoisomerase IV, the DNA becomes hypernegatively
supercoiled. The steady-state level of supercoiling in Escherichia coli is
maintained by a balance between topoisomerase IV, acting in concert with topoisomerase
I, to remove excess negative supercoils and thus acting in opposition to DNA
gyrase.A typical bacterial chromosome contains approximately 50 giant loops of supercoiled
DNA arranged around a protein scaffold. In Figure 4.16, the single line represents
a double helix of DNA and the helixes are the supercoils.
The video reads from the aforementioned textbook almost word for word. The video is also consistent with your comment. What is the specific problem?
"Type II topoisomerases (DNA Gyrase of E.coli). The gyrase enzyme grabs DNA and, in an ATP-dependent process, introduces a double-strand break, passes another part of the double helix through the break, and then reseals the break. The end result is the introduction of a negative supercoil" (Microbiology: An evolving science p 247)
Type I topoisomerases cleave only one strand of a double helix and are generally used to relieve or unwind supercoils. Type 1 enzymes are usually single proteins. (p247)