base analogs related to DNA

1. BASE
ANALOGS
BIBHU PRASAD
RATH
LECT. IN BOTANY

2. Which one of the following is a base
analogue [BHU 1984]
• A) Nitrous acid
• B) Colchicine
• C) 5 - bromouracil
• D) Caffeine acycloguanosine

3. • Base analogues are molecules that can
substitute for normal bases in nucleic acids.
• Base analogs are molecules which have a very
similar structure to one of the four
nitrogenous bases which are used in DNA
(adenine, guanine, cytosine or thymine).
5-bromouracil

4. • Usually, substitution of a base analogue will
result in altered base pairings and structural
changes that affect DNA replication and
transcription of genes.
• 5-bromouracil, 2-aminopurine, 6-
mercaptopurine, and acycloguanosine
2-aminopurine

5. • Since 5-bromouracil can pair with either
adenine or guanine, it also affects base
pairing during DNA replication, which leads
to mutations.
• An analogue of adenine, 2-aminopurine, also
causes mutations in a similar way since it can
pair with either T or C.
6- mercaptopurine

6. • Neoplasm, a new and abnormal
growth of tissue in a part of the
body, especially as a
characteristic of cancer.
• 5-Bromouracil is used to treat
neoplasms.
Image courtesy:
https://en.wikipedia.org/wiki/Neoplasm