12.3. NUCLEIC ACiDS
317
NAME
Glycine
Alanine
Valine
Threonine
SYMBOL M ,
, Da
RNA WORDS
STRUCTURE
sized, nm (CODONS)
G ~ Y
Ala
Val
Thr
Glutamate
(Glutamic acid)
Tryptophan
Try
75.07 Da
0.42 nrn
89.09 Da
0.47 nm*
117.12 Da
0.54 nm
119.12 Da
0.54 nm
147.13 Da
0.70 nm
246.27 Da
0.90 nm
NH, - CHz- COOH
GGU GGA
GGC GGG
" 2
I
GCU GCC GCG GCA
CH3-C-COOH
,
H
H NH,
CH3
I
GUU GUA
'L-CCOOH
GUC GUG
C H j
/,
H NH,
I 1
ACU ACA
C H s - G C -
COOH
ACC ACG
L A
H
"2
I
I
GAA GAG
HOOC-CH,-CH2-C-COOH
H
"2
C
1
I
c 4 ' cC-CH,-C-COOH
H
UGG
I
II
II
C\C/C,N/CH
H
Figure 12.5. Names, symbols, molecular weights &, size parameters d, three-letter RNA
genetic codewords (codons), and structures 01 6 of the 20 amino acids, with the smallest amino
acid, glycine, at the top, and the largest, tryptophan. at the bottom.
R
O
F r o
R
O
HzN-C-C-OH
+ H,N-C-C-OH
+ H,N-C-C-OH
I II
I II
I II
I
I
H
I
H
Before bonding
H
R O H R ' O H R ' O
I I I I I I I I I l l
I
HzN- C - C- N - C - C- N- C- C - OH +2H20
I
H
I
H
Alter bonding
H
Figure 12.6. Formation of a tripeptide chain (bottom) by establishing peptide bonds between
three amino acids (lop).