Molecular orbitals protein chromophores

We extend our considerations of the micro-environment imposed by the protein to the thesis that axial ligands, hydrogen bonds and neighboring residues of photo synthetic chromophores help to define a scaffolding that in turn controls the conformations of the molecules. Theoretical calculations indicate that conformational variations would shift the highest occupied (HOMO) and lowest unoccupied (LUMO) molecular orbitals of (B)Chls and thereby modulate their redox and light-absorption properties [17,32]. We consider here the evidence for and the consequences of such conformational differences in (B)Chls, and test our conclusions with a series of synthetic porphyrins that are significantly puckered. 

---