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.
Negative supercoils make the DNA loose. Positive supercoils introduce more writhes, i.e., basically make the whole DNA structure more complex. Hence, it becomes to harder to denature positively supercoiled DNA.
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)
![Lp. Сердце Вселенной #60 РОЖДЕНИЕ ЛОЛОЛОШКИ [Финал] • Майнкрафт](http://i.ytimg.com/vi/YoR0pAV9FVQ/mqdefault.jpg)
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!!!
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.
ua-cam.com/video/aD67gi6bXws/v-deo.html
Love it, it made this concept really easy. Thanks!
she is like seedhi baat no bakwas awesome video .... very helpful
Wonderful video! This makes so much more sense than just reading it.
you have done god's work here. thank you
Note to self; use the animation of 2 kinds of topoisomeres for visualization
Beautiful explanation. thank you!
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.
ua-cam.com/video/aD67gi6bXws/v-deo.html
Thank you for the amazing video
A small inaccuracy: the ATPase of DNA Gyrase is GyrB not GyrA
And were expected to believe this complex of a process for literal auto repair of DNA came about purely by chance? GEN 1:1
The best video on supercoiling on youtube! thanks
why is the DNA cut in the first place?
So, human DNA is negatively supercoiled. Thank you for the information!
Great video👌so helpful
Perfect explanation,thank you
The animation is incorrect, top 1 doesnt create a separation of the two strands of the DNA
Thanked helped me out big time
Love this 😍😍😍😍😍😍😍
Thanks, it was really helpful.
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.
Why is DNA more difficult to replicate using positive supercoils yet they make the DNA loose?
Negative supercoils make the DNA loose. Positive supercoils introduce more writhes, i.e., basically make the whole DNA structure more complex. Hence, it becomes to harder to denature positively supercoiled DNA.
Very well explained ty!
Excellent animation
thanks a lot! this is great!
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.
ua-cam.com/video/aD67gi6bXws/v-deo.html
@@goofygoober6211 it really helps me to understand. ua-cam.com/video/aD67gi6bXws/v-deo.html
thanque so much love from india
Great and helpfull tnx alot
Excellent
Thanks a lot nice explanation
awsome, thanks.
Pie se maksute? Aku gapaham😢 artine
amazing
Thank u💛💛
Wow.. Thank u💙
buenisimo!☺
very well
Ok....
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)
This is fucking confusing