What is the Difference Between Positive and Negative Supercoiling of DNA?
🆚 Go to Comparative Table 🆚The difference between positive and negative supercoiling of DNA lies in the direction of coiling and the number of twists in the DNA strand compared to its relaxed state.
- Positive Supercoiling: In this process, the DNA strand is overwound compared to its relaxed state, with the double-helical conformation twisted tighter in a left-handed direction. Positive supercoiling is also known as "overwinding". It occurs during specific cellular functions and is not present in DNA during normal states.
- Negative Supercoiling: In this process, the DNA strand is underwound compared to its relaxed state, with the double-helical conformation twisted looser in a right-handed direction. Negative supercoiling is also known as "underwinding". Most organisms have negatively supercoiled DNA in their normal state, and it is advantageous for processes like DNA replication and transcription.
In summary, the key difference between positive and negative supercoiling of DNA is the direction of coiling and the number of twists in the DNA strand. Positive supercoiling results in an overwound DNA strand, while negative supercoiling results in an underwound DNA strand compared to the relaxed state.
Comparative Table: Positive vs Negative Supercoiling of DNA
Here is a table comparing the differences between positive and negative supercoiling of DNA:
| Feature | Positive Supercoiling | Negative Supercoiling |
|---|---|---|
| Definition | A process where the DNA strand is overwound compared to its relaxed state. | A process where the DNA strand is underwound compared to its relaxed state. |
| Direction | Occurs towards the right-hand side. | Occurs towards the left-hand side. |
| Cellular Effects | Occurs during specific cellular functions. | Prevalent in most organisms, including bacteria and humans. |
| DNA Structures | Produces plectonemes or toroids, sometimes a combination of both. | Produces plectonemes or toroids, sometimes a combination of both. |
| Helix Twisting | Caused by extra helical twists. | Caused by subtractive twisting. |
| Topoisomerase Enzymes | Type I topoisomerase can only relieve positively supercoiled DNA. | Type I topoisomerase can only relieve negatively supercoiled DNA. |
Positive and negative supercoiling are present in all organisms, from bacteria to humans. Both types of supercoiling play essential roles in various cellular processes, such as DNA replication and transcription, facilitated by topoisomerase enzymes.
- Positive vs Negative Ion
- Positive vs Negative Zeta Potential
- Positive vs Negative Gene Regulation
- Positive vs Negative Sense RNA Virus
- Electropositive vs Electronegative
- Linear vs Circular DNA
- ssDNA vs dsDNA
- O Positive vs O Negative
- Positive vs Negative Tropism
- Genomic vs Plasmid DNA
- Positive vs Negative Selection of T Cells
- Positive vs Negative Control
- Positive vs Negative Allosterism
- Paramagnetic vs Superparamagnetic
- Helicase vs Topoisomerase
- Plasmid DNA vs Chromosomal DNA
- B DNA vs Z DNA
- Coding vs Noncoding DNA
- Positive vs Negative Feedback Loops