fulltext.study @t Gmail

The role of the PsbU subunit in the light sensitivity of PSII in the cyanobacterium Synechococcus 7942

Paper ID Volume ID Publish Year Pages File Format Full-Text
30917 44514 2011 8 PDF Available
Title
The role of the PsbU subunit in the light sensitivity of PSII in the cyanobacterium Synechococcus 7942
Abstract

In the present study we investigated the role of the PsbU subunit in the electron transport characteristics and light sensitivity of the Photosystem II complex. The experiments were performed by using an earlier characterized PsbU-less mutant of the cyanobacterium Synechococcus   PCC 7942, which has enhanced antioxidant capacity (Balint et al. FEBS Lett. 580 (2006) 2117–2122). Flash induced Chl fluorescence measurements in the presence and absence of the electron transport inhibitor DCMU showed that both the S2QA- and the S2QB- recombination is slowed down in the PsbU mutant relative to the WT strain. Thermoluminescence measurements confirmed the increased stability of the S2QA- and S2QB- charge pairs by showing an increased peak temperature of Q and B bands, which were measured in the presence and absence of DCMU, respectively. In addition, the intensity of the TL bands is also increased in the PsbU mutant (≈1.7 times for the B band), as compared to the WT. The PsbU mutant shows enhanced loss of Photosystem II activity under exposure to high light intensity both in the absence and presence of the protein synthesis inhibitor lincomycin. It is concluded from the data that the lack of the PsbU subunit in Synechococcus   PCC 7942 affects the energetic stability of the S2QA- and S2QB- charge pairs by modifying both the PSII donor and acceptor side components. This effect is most likely caused by structural changes in the vicinity of the Mn cluster and in the inner part of the PSII complex, which are induced by the lack of the PsbU subunit from the lumenal part of the complex. The light sensitivity of Photosystem II in Synechococcus 7942 in the absence of the PsbU subunit is likely due to reactive oxygen species, which are produced as a consequence of disturbed donor side structure and/or due to the modified energetic properties of the primary radical pair.

► The role of the PsbU subunit of Photosystem II was investigated in Synechococcus 7942. ► PsbU affects both donor (S2 state) and acceptor side components (QA, QB) of PSII. ► The light sensitivity of PSII is increased in the absence of PsbU. ► ROS production and modified properties of P680+Phe− are involved in light sensitivity.

Keywords
Cyanobacterium; Synechococcus 7942; Photoinactivation; PsbU subunit; Reactive oxygen species
First Page Preview
The role of the PsbU subunit in the light sensitivity of PSII in the cyanobacterium Synechococcus 7942
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 105, Issue 2, 3 November 2011, Pages 149–156
Authors
, , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us