Nucleic Acids: Their types and applications

1. SHRI SHANKARACHARYA MAHAVIDYALAYA
Junwani- BHILAI
NUCLEICACIDS
By:
VIKASCHANDRASHARMA,
ASST. Prof.,departmentof chemistry

2. Nucleic Acids and Nucleic Acid Structure
• The nucleic acids are made up of polymers of four different
nucleotide residues each.
• RNA uses AMP, CMP, GMP, and UMP
• DNA use the deoxy forms:
dAMP, dCMP, dGMP, and dTMP.
• The two nucleic polymers differ by both the 2‘ functional
group (-OH or -H) and the use of either uridine or thymine as
the fourth base...

3. NUCLEOTIDE:-
A nucleotide
is an organic
molecule made up of
a nucleotide base, a
five-carbon sugar
(ribose or
deoxyribose) and at
least one phosphate
group. Nucleotides
make up the basic
units of DNA and RNA
molecules.

4. Nucleosides:- are glycosylamines consisting of a nucleobase (often
referred to as simply base) bound to a ribose or deoxyribose sugar
via a beta-glycosidic linkage. Examples of nucleosides include
cytosine, uridine, adenosine, guanosine, thymidine and inosine.

5. DNA is double-stranded, with complementary
basepairing.

6. The Double Helix

7. Types of DNA Double Helix
Type A: major conformation of RNA, minor conformation
of DNA;
Type B: major conformation of DNA;
Type Z: minor conformation of DNA
Stability of DNA:-
• Stacking interactions stabilize the double helix about
as much as the base-pair H-bonds.
• Stacking interactions are not sufficient to
overcome the electrostatic repulsion of the
phosphates.
• The H-bonding guarantees the complementarily of
the strands..

8. Watson Crick Base pairing

9. Features of the Watson Crick pairing
1. The permitted hydrogen bonds are: adenine with
thymine (2 bonds); and, cytosine with guanine (3
bonds).
2. The dimensions of the 2 permitted base-pairs are
similar, i.e. the C1'-C1' distance is nearly
identical in both cases.
3. The beta-glycosidic bond is attached on the same
edge of the base pair.
4. Although some of the atoms in the purine and
pyrimidine bases are involved in hydrogen bonds,
there is still potential for further hydrogen
bonding. This potential is particularly important for
sequence specific protein binding.

10. α (bond to 5'-O) and ζ
(bond to previous 3'-O).
Phosphate is tetrahedral
like carbon, so favoured
conformations occur at
±g (gauche, ±60o) or t
(extended, 180o). α (bond to 5'-O) and ζ
(bond to previous 3'-O).
Phosphodiester bonds:-

11. Nucleotides
are
linked
by
phosphodiester
bonds
Strand has a
direction
(5'→3')

12. DNADuplication

13. Tertiary Structure of DNA

14. STRUCTURAL CHANGES IN DNA MELTING

15. RNA & ITS TYPE
• RNA: RNA is mostly an adaptor molecule, used to
translate
between information in D NA and protein
machinery/structure.
Both RNA and proteins are involved in catalysis.
• mRNA - a transcription of the information in the DNA.
Used to
carry the information in temporary format from the
DNA archive to the protein synthetic machinery..
 rRNA - This RNA forms the core of a large molecular
machine, the
ribosome, which is used to make proteins. The
ribosome consists
of 3-4 RNA molecules and many proteins (~100 in
eukaryotes).

16. RNA Structural Elements

17. tRNA Structure

18. Use in medicine andtechnology
• In medicine, several nucleoside analogues are used as antiviral
or anticancer agents. These compounds are activated in the
cells by being converted into nucleotides.
• In molecular biology, several analogues of the sugar backbone
exist. Due to the low stability of RNA, which is prone to
hydrolysis, several more stable alternative
nucleoside/nucleotide analogues that correctly bind to RNA
are used. This is achieved by using a different backbone sugar.
These analogues include LNA, morpholino, PNA.
• In sequencing, dideoxynucleotides are used. These nucleotides
possess the non-canonical sugar dideoxyribose, which lacks 3'
hydroxyl group (which accepts the phosphate). It therefore
cannot bond with the next base and terminates the chain, as
DNA polymerases cannot distinguish between it and a regular
deoxy ribonucleotide.