Donor–acceptor symmetric and antisymmetric tunneling matrix elements: a pathway model investigation of protein electron transfer

In protein electron transfer reaction rate calculations, the electronic Hamiltonian is apportioned into donor–acceptor ( D – A ) and protein bridge subspaces, and a two-state system is defined for the D – A subspace. Löwdin partitioning is used to perform the two-state reductions necessary to comput...

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Bibliographic Details
Published in:Journal of molecular modeling 2019-03, Vol.25 (3), p.64-9, Article 64
Main Authors: de Andrade, P. C. P., Guerra, J. C. O.
Format: Article
Language:English
Subjects:
Characterization and Evaluation of Materials
Chemistry
Chemistry and Materials Science
Computer Appl. in Life Sciences
Computer Applications in Chemistry
Coupling
Electron transfer
Electron tunneling
Mathematical analysis
Matrix methods
Molecular Medicine
Original Paper
Proteins
Subspaces
Theoretical and Computational Chemistry
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Summary:In protein electron transfer reaction rate calculations, the electronic Hamiltonian is apportioned into donor–acceptor ( D – A ) and protein bridge subspaces, and a two-state system is defined for the D – A subspace. Löwdin partitioning is used to perform the two-state reductions necessary to compute the tunneling matrix element between D and A sites. Here, a method of performing donor and acceptor state analysis for a non-orthogonal basis set in both the weak and strong electronic coupling regimes is developed. The electron tunneling current and coupling are obtained in terms of D – A symmetric and antisymmetric interatomic tunneling elements, and are then used to compare pathway models. These interatomic tunneling elements are both proportional to the Green’s function elements of the isolated protein bridge. To facilitate a perturbative treatment of antisymmetric interatomic tunneling currents, we found a well-known expression for the D – A tunneling matrix element in terms of transformed Green’s function matrix elements of the isolated protein bridge. Also, the relationship of the tunneling matrix element to BO pathways is discussed using the symmetric interatomic coupling. Finally, the definition of the average interatomic and atomic pathway coupling allows us obtain the quantum interference between interatomic tunneling pathways.
ISSN:1610-2940
0948-5023
DOI:10.1007/s00894-019-3936-4