Biology Reference
In-Depth Information
148
by experimentally observed values. In short, the simple-minded theoretical
calculations discussed in the previous Chapter do not tell the entire story.
Many factors are beyond our comprehension at this time.
Therefore, proteins with known three-dimensional structures will be used as
references. Most of these are soluble proteins that have been crystallized.
Even though their atoms cannot be visualized directly from X-ray
diffraction studies due to insufficient resolution, atomic coordinates for all
non-hydrogen atoms are usually provided with the incorporation of the
standard peptide units. From these, the angles of each residues can be
determined as discussed in detail in the precious Chapter. Together with the
sequences of these reference proteins, their
angles will provide the
necessary information for predicting protein folding.
For example, the first 26 amino acid residues of myoglobin are listed in
Table 6-1 together with their angles in the new convention. Due to the
flexibility of the N-terminal end, the
angles of Val at position 1 are not
determined.
Table 6-1.
angles of residues 2 to 26 of myoglobin.
Position
Amino Acid Residue
angles
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Val
Leu
Ser
Glu
Gly
Glu
Trp
Gln
Leu
Val
Leu
His
Val
Trp
Ala
Lys
Val
Glu
Ala
-47
0
,+134
0
-50
0
,+149
0
-48
0
,-55
0
-54
0
,-55
0
-53
0
,-40
0
-62
0
,-49
0
-40
0
,-57
0
-64
0
,-47
0
-52
0
,-49
0
-63
0
,-41
0
-66
0
,-33
0
-66
0
,-44
0
-51
0
,-64
0
-41
0
,-36
0
-73
0
,-46
0
-61
0
,-32
0
-69
0
,-9
0
-71
0
,-35
0
