Z - DNA: comparison with A-DNA and B-DNA
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- Опубліковано 11 вер 2024
- The most common form of DNA that occurs in living organisms is B-form or Watson and Crick's model of DNA. Under certain conditions, this form changes its configuration.
There are 6 different morphological forms of DNA: A, B, C, D, E and Z. Three biologically active forms of DNA are A-DNA, B-DNA, and Z-DNA.
A-DNA: this form is double-stranded, right-handed helical DNA. It is a dehydrated form that occurs in an environment richer in Na+ and less water. It shows 11 base pairs per turn of the helix and a diameter of 23 A. The height of the pitch is 28 A and axial rise is 2.56 A. The sugar-phosphate backbone is regular. The repeating units are mononucleotides. It shows the presence of 2 deep groves and 2 shallow groves.
B-DNA: occurs at low salt concentration and a high degree of hydration (i.e. normal conditions).
Z-DNA: Rich et al. working at MIT, USA studied the molecular structure of DNA fragments at atomic resolution. They proposed a Z-form of DNA along with B-DNA.
The Z-DNA shows the following characteristics:
It is stabilized by high salt concentration.
It is left-handed DNA.
It is a double-helical structure with a zig-zag sugar-phosphate backbone.
In Z-DNA, the repeating unit is a dinucleotide and the sugar residues have an alternating orientation of dinucleotide.
In Z-DNA, 12 base pairs are present per turn.
The height of the pitch is 45 A.
The diameter of the helix is 18 A
For additional information about DNA and Nucleic acids, you can also refer to
• Watson and Crick's Mod... (“Watson and Crick’s model of DNA: Part-I (Characteristics)”- The video explains characteristics of DNA molecule with suitable models.)
• Nucleic Acids: Composi... ("Nucleic Acid Composition Part-I" Video describes various components of nucleic acids and gives a simple trick to draw and remember the structure of nitrogen bases, ribose and deoxyribose sugars. )
• Nucleic Acid Compositi... (‘Nucleic Acid Composition Part-II: Formation of polynucleotide and nomenclature of N, NS and NT’)
• Nucleic Acids: Made it... ("Nucleic Acids: Made it easy" )
U are amazing sir!!🙏🏻 this is so confusing topic...and u made it very easy for the students!🙏🏻 thanks a ton ,sir!🙌
Thank you Swapnil.
@@DrSudhakarKhot pleasure sir!🙏🏻🙏🏻
Real clg mde offline lectures hotE tva kadi pat jhale nahi. BUT Online you tube lectures attended karunch pat jhale.. SIR EK NUMBER GREAT SIR
Thank you Uday Sir
Thank you so much read watson mol bio but was missing some concepts so can visualize with the model! Thank you very much🎉❤
Wonderful explanation sir
Such briliant lecture sir DNA helical structure.I am lucky sir because I am your student sir
Wish you Best of Luck Sampada.
Thank you sir
Such a nice explanation.. 👌
Where is various RNA forms,DNA replication and gene regulation...??? Plzz make videos on these topics,sir...
Thanks for your comments. Surely within next few days I will upload the videos on RNA and DNA replication.
@@DrSudhakarKhot thank you sir 😊.... Waiting.
Amazing explanation ❤
Nice Idea of helical structure Sir...
It is my badluck sir that I am not your student. 😍🙏
Thank you for your complements.
Very nice information
Thank you Sir. Plz keep watching and share with your students.
Sir please do more videos on topics like Carbohydrates,Amino acids, peptides,Proteins, Enzymes, Lipids and Nucleic acids for BSc level... please
Sure. 👍
Excellent explanation
Thank you Madam, please share it with your students.
Please tell in which form of DNA syn- & anti- conformation around the glycosidic bond are present?