314 11 Alignment of Primary and Three-Dimensional Structures of Proteins
Analysis of the Three-Dimensional Structures of Proteins
Within the Same Family
The above three-dimensional structure analysis can be carried out within the
same family. For example, in the analysis of the serpin ensemble, there is
only one super-family in this fold, with only one family in this super-family,
whose ID numbers in PDB are given as 7apiA, 8apiA, 1hleA, 1ovaA, 2achA,
9apiA, 1psi, 1atu, 1ktc, 1athA, 1antI, 2antI. These are from antitrypsin, elas-
tase, inhibitor, ovalbumin, antichymotrypsin, and antitrypsin, antithrombin,
respectively, in humans, horses, and cattle.
The result of their three-dimensional structure alignment is shown in
Table 11.5. Except for protein pdb1ktc, the characteristic sequences of the
three-dimensional structures of other protein backbones show comparatively
high homologies.
Remark 15. Table 11.6 shows the multiple alignment result of the three-
dimensional structure characteristic sequences of each serpin ensemble pro-
tein. Because of the complexity of the structure of protein PDB1KTCA, it is
not listed in this table. Also, the value 4 stands for the virtual symbol “−”.
Remark 16. In Table 11.7, A, B stand for the alignment result of the torsion
angle phase sequences of the serpin ensemble protein PDB1ATHA and protein
PDB8APIA, where 4 and − stand for the virtual symbol “−”. The inserted
symbols in the primary structures are determined by the corresponding posi-
tions of the insert symbols of the three-dimensional structure alignment.
Remark 17. We can see from Tables 11.7 and 11.8 that for the proteins
PDB1ATHA and PDB8APIA, in the regions where the three-dimensional
structures are homologous (such as sites 5–28, sites 32–67, etc.), the corre-
sponding primary structures are quite different. It shows that, in proteins
or peptide chains, primary structures which are quite different may generate
similar three-dimensional structures.
11.2.3 Example of Computation in Consecutive Case
If the torsion angle ψ is considered a variable whose value ranges in the in-
terval (−π, π), Ψ
1
and Ψ
2
are two vectors who take values in (−π,π). Their
alignment can also be implemented by the dynamic programming algorithm.
The statistical table of the average absolute deviation alignment of the torsion
angle of the protein PDB1BF9 backbone is shown in Tables 11.9 and 11.10.
Remark 18. In Tables 11.9 and 11.10, each value is in radians. They are both
statistical tables of the average absolute deviation alignment of the torsion
angles for the first 15 models of protein PDB1BF9, where Table 11.9 shows the
average absolute deviation of the torsion angles of all models, while Table 11.10
shows the average absolute deviation of the stable region of the torsion angle
phase (from the fourth amino acid to the 31st amino acid) of each model.