Simple Derivation of the Dyson Equation

If it is assumed that we work again with a nonorthogonal basis set Xr), then the unperturbed problem assumes the form 

The Green matrix of this system can be given, by analogy with expression (4.37), as 

The expression (4.40) finally yields the Dyson equation from (4.44) in the form 

Effect of Side-Chain Disorder on the Eiectronic Structure of Proteins 

In the calculations of the electronic structure of these polypeptides, we applied the all-valence electron MINDO crystal-orbital method in its MINDO/3 parametrization. The calculations involved atomic coordinates corresponding to the antiparallel-) -pleated-sheet structure of Pauling and Corey S hence we had a combined symmetry operation in the case of poly( y) each gly unit was obtained in this polymer from its neighboring one by a translation along the helical axis through 3.25 A and by a simultaneous 180° rotation around it. In order to preserve the cyclic property of the Fock hypermatrix of the whole polymer (which is 

---