The University of Southampton
University of Southampton Institutional Repository

Accessory chlorophyll proteins in cyanobacterial photosystem I

Accessory chlorophyll proteins in cyanobacterial photosystem I
Accessory chlorophyll proteins in cyanobacterial photosystem I
The IsiA protein accumulates in many cyanobacteria under conditions of iron starvation. It is a Chl a-binding protein, which is closely related to the six-transmembrane ?-helical antenna family typified by CP43 of PS II. One of its functions is to provide an efficient accessory light harvesting system for Photosystem I (PS I) by forming a ring of 18 IsiA subunits around the trimeric reaction center core. This response is probably to compensate for a drop in the PS I level relative to Photosystem II (PS II) and, the level of phycobiliproteins, in response to iron deficiency. A similar accessory light harvesting system for PS I has been shown to occur in cyanobacteria that do not contain phycobiliproteins, often termed prochlorophytes. This light harvesting system is composed of Pcb proteins that are closely related to IsiA but bind Chl b as well as Chl a. Unlike IsiA, Pcb proteins can also provide accessory light harvesting systems for PS II. Some cyanobacteria contain phycobiliproteins and Pcb proteins, where both are able to function as light harvesting systems. In one case the Pcb protein seems to bind only Chl a (Fischerella muscicola) while in another they bind Chl a (Acaryochloris marina). Sequence analysis indicates that the IsiA/Pcb proteins have very similar pigment binding sites to those of CP43 and to a lesser extent to the other reaction center proteins of this family and have the capacity to accommodate several different forms of Chl. The six-transmembrane ?-helical Chl-binding proteins, of which IsiA and Pcb are members, seem to have evolved from a basic evolutionary building block providing both internal and accessory light harvesting systems for a wide range of photosynthetic organisms.
9781402042553
24
99-117
Springer
Barber, James
3cde30c7-691b-4d0c-bfa4-449895b7f447
Nield, Jon
af10ad21-0721-41b4-86c7-00dcb58458dc
Duncan, James
a94c30d7-68eb-4945-ad4a-ca566cfc78d8
Bibby, Thomas S.
e04ea079-dd90-4ead-9840-00882de27ebd
Golbeck, John H.
Barber, James
3cde30c7-691b-4d0c-bfa4-449895b7f447
Nield, Jon
af10ad21-0721-41b4-86c7-00dcb58458dc
Duncan, James
a94c30d7-68eb-4945-ad4a-ca566cfc78d8
Bibby, Thomas S.
e04ea079-dd90-4ead-9840-00882de27ebd
Golbeck, John H.

Barber, James, Nield, Jon, Duncan, James and Bibby, Thomas S. (2007) Accessory chlorophyll proteins in cyanobacterial photosystem I. In, Golbeck, John H. (ed.) Photosystem I: The Light-Driven Plastocyanin: Ferredoxin Oxidoreductase. (Advances in Photosynthesis and Respiration, 24) Dordrecht, The Netherlands. Springer, pp. 99-117. (doi:10.1007/978-1-4020-4256-0_9).

Record type: Book Section

Abstract

The IsiA protein accumulates in many cyanobacteria under conditions of iron starvation. It is a Chl a-binding protein, which is closely related to the six-transmembrane ?-helical antenna family typified by CP43 of PS II. One of its functions is to provide an efficient accessory light harvesting system for Photosystem I (PS I) by forming a ring of 18 IsiA subunits around the trimeric reaction center core. This response is probably to compensate for a drop in the PS I level relative to Photosystem II (PS II) and, the level of phycobiliproteins, in response to iron deficiency. A similar accessory light harvesting system for PS I has been shown to occur in cyanobacteria that do not contain phycobiliproteins, often termed prochlorophytes. This light harvesting system is composed of Pcb proteins that are closely related to IsiA but bind Chl b as well as Chl a. Unlike IsiA, Pcb proteins can also provide accessory light harvesting systems for PS II. Some cyanobacteria contain phycobiliproteins and Pcb proteins, where both are able to function as light harvesting systems. In one case the Pcb protein seems to bind only Chl a (Fischerella muscicola) while in another they bind Chl a (Acaryochloris marina). Sequence analysis indicates that the IsiA/Pcb proteins have very similar pigment binding sites to those of CP43 and to a lesser extent to the other reaction center proteins of this family and have the capacity to accommodate several different forms of Chl. The six-transmembrane ?-helical Chl-binding proteins, of which IsiA and Pcb are members, seem to have evolved from a basic evolutionary building block providing both internal and accessory light harvesting systems for a wide range of photosynthetic organisms.

This record has no associated files available for download.

More information

Submitted date: 20 May 2006
Published date: 20 May 2007

Identifiers

Local EPrints ID: 66745
URI: http://eprints.soton.ac.uk/id/eprint/66745
ISBN: 9781402042553
PURE UUID: 0745c183-dcf8-4b24-9544-e566afd49633

Catalogue record

Date deposited: 15 Jul 2009
Last modified: 13 Mar 2024 18:37

Export record

Altmetrics

Contributors

Author: James Barber
Author: Jon Nield
Author: James Duncan
Author: Thomas S. Bibby
Editor: John H. Golbeck

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×