Document Detail

Flash-induced consumption of molecular oxygen on the donor side of photosystem II in Mn-depleted subchloroplast membrane fragments: specific effects of manganese and calcium ions.
MedLine Citation:
PMID:  23756831     Owner:  NLM     Status:  Publisher    
It has been shown that removal of manganese from the water-oxidizing complex (WOC) of photosystem II (PSII) leads to flash-induced oxygen consumption (FIOC) which is activated by low concentration of Mn(2+) (Yanykin et al., Biochim Biophys Acta 1797:516-523, 2010). In the present work, we examined the effect of transition and non-transition divalent metal ions on FIOC in Mn-depleted PSII (apo-WOC-PSII) preparations. It was shown that only Mn(2+) ions are able to activate FIOC while other transition metal ions (Fe(2+), V(2+) and Cr(2+)) capable of electron donation to the apo-WOC-PSII suppressed the photoconsumption of O2. Co(2+) ions with a high redox potential (E (0) for Co(2+)/Co(3+) is 1.8 V) showed no effect. Non-transition metal ions Ca(2+) by Mg(2+) did not stimulate FIOC. However, Ca(2+) (in contrast to Mg(2+)) showed an additional activation effect in the presence of exogenic Mn(2+). The Ca(2+) effect depended on the concentration of both Mn(2+) and Ca(2+). The Ca effect was only observed when: (1) the activation of FIOC induced by Mn(2+) did not reach its maximum, (2) the concentration of Ca(2+) did not exceed 40 μM; at higher concentrations Ca(2+) inhibited the Mn(2+)-activated O2 photoconsumption. Replacement of Ca(2+) by Mg(2+) led to a suppression of Mn(2+)-activated O2 photoconsumption; while, addition of Ca(2+) resulted in elimination of the Mg(2+) inhibitory effect and activation of FIOC. Thus, only Mn(2+) and Ca(2+) (which are constituents of the WOC) have specific effects of activation of FIOC in apo-WOC-PSII preparations. Possible reactions involving Mn(2+) and Ca(2+) which could lead to the activation of FIOC in the apo-WOC-PSII are discussed.
D V Yanykin; A A Khorobrykh; S A Khorobrykh; N L Pshybytko; V V Klimov
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-6-12
Journal Detail:
Title:  Photosynthesis research     Volume:  -     ISSN:  1573-5079     ISO Abbreviation:  Photosyn. Res.     Publication Date:  2013 Jun 
Date Detail:
Created Date:  2013-6-12     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100954728     Medline TA:  Photosynth Res     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
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