Document Detail


Modulation of photosynthetic electron transport in the absence of terminal electron acceptors: characterization of the rbcL deletion mutant of tobacco.
MedLine Citation:
PMID:  16038871     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Tobacco rbcL deletion mutant, which lacks the key enzyme Rubisco for photosynthetic carbon assimilation, was characterized with respect to thylakoid functional properties and protein composition. The Delta rbcL plants showed an enhanced capacity for dissipation of light energy by non-photochemical quenching which was accompanied by low photochemical quenching and low overall photosynthetic electron transport rate. Flash-induced fluorescence relaxation and thermoluminescence measurements revealed a slow electron transfer and decreased redox gap between Q(A) and Q(B), whereas the donor side function of the Photosystem II (PSII) complex was not affected. The 77 K fluorescence emission spectrum of Delta rbcL plant thylakoids implied a presence of free light harvesting complexes. Mutant plants also had a low amount of photooxidisible P700 and an increased ratio of PSII to Photosystem I (PSI). On the other hand, an elevated level of plastid terminal oxidase and the lack of F0 'dark rise' in fluorescence measurements suggest an enhanced plastid terminal oxidase-mediated electron flow to O2 in Delta rbcL thylakoids. Modified electron transfer routes together with flexible dissipation of excitation energy through PSII probably have a crucial role in protection of PSI from irreversible protein damage in the Delta rbcL mutant under growth conditions. This protective capacity was rapidly exceeded in Delta rbcL mutant when the light level was elevated resulting in severe degradation of PSI complexes.
Authors:
Yagut Allahverdiyeva; Fikret Mamedov; Pirkko Mäenpää; Imre Vass; Eva-Mari Aro
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  1709     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  2005 Aug 
Date Detail:
Created Date:  2005-08-05     Completed Date:  2005-10-06     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  69-83     Citation Subset:  IM    
Affiliation:
Department of Biology, Plant Physiology and Molecular Biology, Turku University, FIN-20014 Turku, Finland.
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MeSH Terms
Descriptor/Qualifier:
Darkness
Electron Transport
Gene Deletion*
Light
Oxygen / metabolism
Photosynthesis / genetics*
Ribulose-Bisphosphate Carboxylase / deficiency*,  genetics*,  metabolism
Thermoluminescent Dosimetry
Tobacco / genetics*,  metabolism
Chemical
Reg. No./Substance:
7782-44-7/Oxygen; EC 4.1.1.39/RbcL protein, plastid; EC 4.1.1.39/Ribulose-Bisphosphate Carboxylase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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