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Fine Tuning of Chlorophyll Spectra by Protein‐Induced Ring Deformation
Author(s) -
Bednarczyk Dominika,
Dym Orly,
Prabahar Vadivel,
Peleg Yoav,
Pike Douglas H.,
Noy Dror
Publication year - 2016
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201512001
Subject(s) - tetrapyrrole , chlorophyll , photosynthesis , chlorophyll a , tryptophan , chemistry , biophysics , biology , biochemistry , amino acid , organic chemistry , enzyme
The ability to tune the light‐absorption properties of chlorophylls by their protein environment is the key to the robustness and high efficiency of photosynthetic light‐harvesting proteins. Unfortunately, the intricacy of the natural complexes makes it very difficult to identify and isolate specific protein–pigment interactions that underlie the spectral‐tuning mechanisms. Herein we identify and demonstrate the tuning mechanism of chlorophyll spectra in type II water‐soluble chlorophyll binding proteins from Brassicaceae (WSCPs). By comparing the molecular structures of two natural WSCPs we correlate a shift in the chlorophyll red absorption band with deformation of its tetrapyrrole macrocycle that is induced by changing the position of a nearby tryptophan residue. We show by a set of reciprocal point mutations that this change accounts for up to 2/3 of the observed spectral shift between the two natural variants.