Fine Tuning of Chlorophyll Spectra by Protein-Induced Ring Deformation

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 specifi...

Full description

Saved in:
Bibliographic Details
Published in:Angewandte Chemie 2016-06, Vol.128 (24), p.7015-7019
Main Authors: Bednarczyk, Dominika, Dym, Orly, Prabahar, Vadivel, Peleg, Yoav, Pike, Douglas H., Noy, Dror
Format: Article
Language:English
Subjects:
Brasses
Chemistry
Chlorophyll
Chlorophylls
Deformation
Lichtsammelkomplexe
Proteins
Residues
Robustness
Spectra
Spektrale Abstimmung
Strukturaufklärung
Tuning
Wasserlösliches Chlorophyllbindeprotein
Citations: Items that this one cites
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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. Provoziertes Erröten: Eine neue Kristallstruktur von wasserlöslichem Chlorophyllbindeprotein (WSCP) des Typs IIa aus Blumenkohl wird mit der Typ‐IIb‐WSCP‐Struktur verglichen. Dabei zeigt sich, wie Ringdeformation zur Rotverschiebung der Qy‐Bande von Chlorophyll genutzt werden kann. Eine einzelne Mutation von Asn zu Ala ändert das H‐Brückenmuster eines Trp‐Restes, wodurch dieser repositioniert und die Planarität des Chlorophyllmakrocyclus gestört wird.
ISSN:0044-8249
1521-3757
DOI:10.1002/ange.201512001