Essential Cell Biology 5th edition

79
NOMENCLATURE
The names can be confusing, but the abbreviations are clear.
base
BASE
adenine
guanine
cytosine
uracil
thymine
NUCLEOSIDE
adenosine
guanosine
cytidine
uridine
thymidine
ABBR.
A
G
C
U
T
Nucleotides and their derivatives can be
abbreviated to three capital letters.
Some examples follow:
AMP = adenosine monophosphate
dAMP = deoxyadenosine monophosphate
UDP = uridine diphosphate
ATP = adenosine triphosphate
sugar
BASE + SUGAR = NUCLEOSIDE
base
P
sugar
BASE + SUGAR + PHOSPHATE = NUCLEOTIDE
NUCLEIC ACIDS
To form nucleic acid polymers, nucleotides
are joined together by phosphodiester
bonds between the 5’ and 3’ carbon
atoms of adjacent sugar rings. The linear
sequence of nucleotides in a nucleic acid
chain is abbreviated using a one-letter
code, such as AGCTT, starting with the
5’ end of the chain.
O
– O P O CH 2
O
O –
sugar
+
base
NUCLEOTIDES AND THEIR DERIVATIVES HAVE
MANY OTHER FUNCTIONS
1 As nucleoside di- and triphosphates, they carry chemical energy in their
easily hydrolyzed phosphoanhydride bonds.
phosphoanhydride bonds
O O
– O P O P O
O – O –
O
P
O –
O
CH 2
O
N
N
NH 2
N
N
OH
example: ATP (or ATP )
OH
OH
O
– O P O CH 2
O
O –
sugar
OH
H 2 O
O 5’ end of chain
– O P O
5’
CH 2
O
O –
sugar
3’
phosphodiester
O
bond
– O P O
O
5’ CH 2
O
base
base
base
NH
2 They combine with other groups to form coenzymes.
2
N
N
H H O H H O H CH 3 H O O
N
N
HS C C N C C C N C C C C O P O P O CH 2
O –
O
H H H H H H HO CH H O –
3
example: coenzyme A (CoA)
O OH
O P O –
3 They are used as small intracellular signaling molecules in the cell.
O –
NH 2
example: cyclic AMP
N
N
CH 2
N
O
N
O
example: DNA
sugar
O
P
O
OH
3’ end of chain 3’ OH
O –
Panel 2.07b