Universität zu Köln

Harrop, Stephen J., Wilk, Krystyna E., Dinshaw, Rayomond, Collini, Elisabetta ORCID: 0000-0002-1019-9100, Mirkovic, Tihana, Teng, Chang Ying, Oblinsky, Daniel G., Green, Beverley R., Hoef-Emden, Kerstin, Hiller, Roger G., Scholes, Gregory D. and Curmi, Paul M. G. (2014). Single-residue insertion switches the quaternary structure and exciton states of cryptophyte light-harvesting proteins. Proc. Natl. Acad. Sci. U. S. A., 111 (26). S. E2666 - 10. WASHINGTON: NATL ACAD SCIENCES. ISSN 0027-8424

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Abstract

Observation of coherent oscillations in the 2D electronic spectra (2D ES) of photosynthetic proteins has led researchers to ask whether nontrivial quantum phenomena are biologically significant. Coherent oscillations have been reported for the soluble light-harvesting phycobiliprotein (PBP) antenna isolated from cryptophyte algae. To probe the link between spectral properties and protein structure, we determined crystal structures of three PBP light-harvesting complexes isolated from different species. Each PBP is a dimer of alpha beta subunits in which the structure of the alpha beta monomer is conserved. However, we discovered two dramatically distinct quaternary conformations, one of which is specific to the genus Hemiselmis. Because of steric effects emerging from the insertion of a single amino acid, the two alpha beta monomers are rotated by similar to 73 degrees to an open configuration in contrast to the closed configuration of other cryptophyte PBPs. This structural change is significant for the light-harvesting function because it disrupts the strong excitonic coupling between two central chromophores in the closed form. The 2D ES show marked cross-peak oscillations assigned to electronic and vibrational coherences in the closed-form PC645. However, such features appear to be reduced, or perhaps absent, in the open structures. Thus cryptophytes have evolved a structural switch controlled by an amino acid insertion to modulate excitonic interactions and therefore the mechanisms used for light harvesting.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Harrop, Stephen J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wilk, Krystyna E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Dinshaw, Rayomond UNSPECIFIED UNSPECIFIED UNSPECIFIED Collini, Elisabetta UNSPECIFIED orcid.org/0000-0002-1019-9100 UNSPECIFIED Mirkovic, Tihana UNSPECIFIED UNSPECIFIED UNSPECIFIED Teng, Chang Ying UNSPECIFIED UNSPECIFIED UNSPECIFIED Oblinsky, Daniel G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Green, Beverley R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hoef-Emden, Kerstin UNSPECIFIED UNSPECIFIED UNSPECIFIED Hiller, Roger G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Scholes, Gregory D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Curmi, Paul M. G. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-434816
DOI:	10.1073/pnas.1402538111
Journal or Publication Title:	Proc. Natl. Acad. Sci. U. S. A.
Volume:	111
Number:	26
Page Range:	S. E2666 - 10
Date:	2014
Publisher:	NATL ACAD SCIENCES
Place of Publication:	WASHINGTON
ISSN:	0027-8424
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language PHOTOSYNTHETIC MARINE-ALGAE; QUANTUM COHERENCE; ENERGY-TRANSFER; CRYSTALLOGRAPHIC STRUCTURE; PHYCOCYANIN; EVOLUTION; SOFTWARE; DYNAMICS; PHYCOERYTHRIN; SPECTROSCOPY Multiple languages Multidisciplinary Sciences Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/43481