Contribution of bacteriochlorophyll conformation to the distribution of site-energies in the FMO protein
Citation:
MacGowan S.A, Senge M.O, Contribution of bacteriochlorophyll conformation to the distribution of site-energies in the FMO protein, Biochimica et Biophysica Acta - Bioenergetics, 1857, 4, 2016, 427 - 442Download Item:
Abstract:
The structural data for the Fenna-Matthews-Olson (FMO) protein indicate that the
bacteriochlorophylls (BChls) display a significant degree of conformational heterogeneity of
their peripheral substituents and the protein-induced nonplanar skeletal deformations of the
tetrapyrrole macrocycle. As electronic properties of chromophores are altered by such
differences, a conformational effect may influence the site-energies of specific pigments and
thus play a role in mediating the excitation energy transfer dynamics, but this has not yet
been established. The difficulty of assessing this question is shown to be partly the result of
the inability of the sequential truncation approach usually employed to account for
interactions between the conformations of the macrocycle and its substituents and an
alternative approach is suggested. By assigning the BChl atoms to meaningful atom groups
and performing all possible permutations of partial optimizations in a full-factorial design,
where each group is either frozen in the crystal geometry or optimized in vacuo, followed by
excited state calculations on each resulting structure (PM6//ZIndo/S), the specific effects of
the conformations of each BChl component as well as mutual interactions between the
molecular fragments on the site-energy can be delineated. This factorial relaxation procedure
gives different estimates of the macrocycle conformational perturbation than the approach of
sequentially truncating the BChl periphery. The results were evaluated in the context of
published site-energies for the FMO pigments from three species to identify how
conformational effects contribute to their distribution and instances of cross-species
conservation and functional divergence of the BChl nonplanarity conformational contribution
are described.
Sponsor
Grant Number
Science Foundation Ireland (SFI)
P.I. 09/IN.1/B2650
Science Foundation Ireland (SFI)
IvP 13/IA/1894
Author's Homepage:
http://people.tcd.ie/sengemDescription:
PUBLISHEDCited By :4 Export Date: 8 December 2016
Author: SENGE, MATHIAS
Type of material:
Journal ArticleCollections
Series/Report no:
Biochimica et Biophysica Acta - Bioenergetics1857
4
Availability:
Full text availableKeywords:
Fenna-Matthews-Olson (FMO)DOI:
http://dx.doi.org/10.1016/j.bbabio.2016.02.001Metadata
Show full item recordLicences: