Effect of chromophore encapsulation on linear and nonlinear optical properties: the case of "miniSOG", a protein-encased flavin.
Linear and nonlinear spectroscopic parameters of flavin mononucleotide, FMN, have been examined both experimentally and computationally under conditions in which FMN is (1) solvated in a buffered aqueous solution, and (2) encased in a protein that is likewise solvated in a buffered aqueous solution. The latter was achieved using "miniSOG" which is an FMN-containing protein engineered from Arabidopsis thaliana phototropin 2. Although it is reasonable to expect that the encasing protein could have an appreciable effect, certainly on the nonlinear two-photon absorption cross section, we find that replacing the dynamic aqueous environment with the more static protein environment does little to influence the spectroscopic properties of FMN. The experimental and computational studies are consistent in this regard, and this agreement indicates that comparatively high-level computational methods can indeed be used with success on large chromophores with a complicated local environment. The results of the present study facilitate the much-needed development of well-characterized and readily-controlled chromophores suitable for use as intracellular sensitizers and fluorophores.
Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, Odense M, 5230, Denmark. kongsted@sdu.dk.
Nanna H
NH
List
Frederico M
FM
Pimenta
Lotte
L
Holmegaard
Rasmus L
RL
Jensen
Michael
M
Etzerodt
Tobias
T
Schwabe
Jacob
J
Kongsted
Peter R
PR
Ogilby
Ove
O
Christiansen
D029681:Arabidopsis Proteins / Q000737:chemistry*; D005415:Flavins / Q000737:chemistry*; D008958:Models, Molecular; D055095:Optics and Photonics; D056949:Phototropins / Q000737:chemistry*
D029681:Arabidopsis Proteins; D005415:Flavins; D056949:Phototropins