Skip navigation
Skip navigation

Photophysical behavior and assignment of the low-energy chlorophyll states in the CP43 proximal antenna protein of higher plant Photosystem II

Hughes, Joseph; Picorel, Rafael; Seibert, Michael; Krausz, Elmars

Description

We have employed absorption, circular dichroism (CD), and persistent spectral hole-burning measurements at 1.7 K to study the photoconversion properties and exciton coupling of low-energy chlorophylls (Chls) in the CP43 proximal antenna light-harvesting subunit of photosystem II (PSII) isolated from spinach. These ∼683 nm states act as traps for excitation energy in isolated CP43. They "bleach" at 683 nm upon illumination and photoconvert to a form absorbing in the range ∼660-680 nm. We present...[Show more]

dc.contributor.authorHughes, Joseph
dc.contributor.authorPicorel, Rafael
dc.contributor.authorSeibert, Michael
dc.contributor.authorKrausz, Elmars
dc.date.accessioned2015-12-07T22:17:00Z
dc.identifier.issn0006-2960
dc.identifier.urihttp://hdl.handle.net/1885/18333
dc.description.abstractWe have employed absorption, circular dichroism (CD), and persistent spectral hole-burning measurements at 1.7 K to study the photoconversion properties and exciton coupling of low-energy chlorophylls (Chls) in the CP43 proximal antenna light-harvesting subunit of photosystem II (PSII) isolated from spinach. These ∼683 nm states act as traps for excitation energy in isolated CP43. They "bleach" at 683 nm upon illumination and photoconvert to a form absorbing in the range ∼660-680 nm. We present new data that show the changes in the CD spectrum due to the photoconversion process. These changes occur in parallel with those in absorption, providing evidence that the feature undergoing the apparent bleach is a component of a weakly exciton-coupled system. From our photoconversion difference spectra, we assign four states in the Chl long-wavelength region of CP43, two of which are the known trap states and are both highly localized on single Chls. The other two states are associated with weak exciton coupling (maximally ∼50 cm -1) to one of these traps. We propose a mechanism for photoconversion that involves Chl-protein hydrogen bonding. New hole-burning data are presented that indicate this mechanism is distinct to that for narrow-band spectral hole burning in CP43. We discuss the photophysical behavior of the Chl trap states in isolated CP43 compared to their behavior in intact PSII preparations. The latter represent a more intact, physiological complex, and we find no clear evidence that they exhibit the photoconversion process reported here.
dc.publisherAmerican Chemical Society
dc.sourceBiochemistry
dc.subjectKeywords: Excitation energy; Photoconversion process; Hydrogen bonds; Plants (botany); Proteins; Chlorophyll; chlorophyll; proximal antenna protein cp43; unclassified drug; vegetable protein; absorption spectrophotometry; article; bleaching; circular dichroism; ene
dc.titlePhotophysical behavior and assignment of the low-energy chlorophyll states in the CP43 proximal antenna protein of higher plant Photosystem II
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume45
dc.date.issued2006
local.identifier.absfor029901 - Biological Physics
local.identifier.ariespublicationu4113015xPUB4
local.type.statusPublished Version
local.contributor.affiliationHughes, Joseph, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationPicorel, Rafael, Consejo Superior de Investigaciones Cientificas
local.contributor.affiliationSeibert, Michael, National Renewable Energy Laboratory
local.contributor.affiliationKrausz, Elmars, College of Physical and Mathematical Sciences, ANU
local.description.embargo2037-12-31
local.bibliographicCitation.issue40
local.bibliographicCitation.startpage12345
local.bibliographicCitation.lastpage12357
local.identifier.doi10.1021/bi0614683
dc.date.updated2015-12-07T08:00:57Z
local.identifier.scopusID2-s2.0-33749536233
CollectionsANU Research Publications

Download

File Description SizeFormat Image
01_Hughes_Photophysical_behavior_and_2006.pdf434.1 kBAdobe PDF    Request a copy


Items in Open Research are protected by copyright, with all rights reserved, unless otherwise indicated.

Updated:  19 May 2020/ Responsible Officer:  University Librarian/ Page Contact:  Library Systems & Web Coordinator