caa a22 4500 445890177 CHVBK 20180317145613.0 cr unu---uuuuu 170323e20110901xx s 000 0 eng 10.1007/s11120-011-9661-1 doi (NATIONALLICENCE)springer-10.1007/s11120-011-9661-1 New insights into the function of the iron deficiency-induced protein C from Synechococcus elongatus PCC 7942 [Elektronische Daten] [Daniel Pietsch, Gábor Bernát, Uwe Kahmann, Dorothee Staiger, Elfriede Pistorius, Klaus-Peter Michel] Iron limitation has a strong impact on electron transport reactions of the unicellular fresh water cyanobacterium Synechococcus elongatus PCC 7942 (thereafter referred to as S.elongatus). Among the various adaptational processes on different cellular levels, iron limitation induces a strongly enhanced expression of IdiC (iron-deficiency-induced protein C). In this article, we show that IdiC is loosely attached to the thylakoid and to the cytoplasmic membranes and that its expression is enhanced during conditions of iron starvation and during the late growth phase. The intracellular IdiC level was even more increased when additional iron was replenished in the late growth phase. On the basis of its amino acid sequence and of its absorbance spectrum, IdiC can be classified as a member of the family of thioredoxin (TRX)-like (2Fe-2S) ferredoxins. The presence of an iron cofactor in IdiC was detected by inductive coupled plasma optical emission spectrometry (ICP-OES). Comparative measurements of electron transport activities of S.elongatus wild type (WT) and an IdiC-merodiploid mutant called MuD, which contained a strongly reduced IdiC content under iron-sufficient as well as iron-deficient growth conditions, were performed. The results revealed that MuD had a strongly increased light sensitivity, especially under iron limitation. The measurements of photosystem II (PS II)-mediated electron transport rates in WT and MuD strain showed that PS II activity was significantly lower in MuD than in the WT strain. Moreover, P700 + re-reduction rates provided evidence that the respiratory activities, which were very low in the MuD strain in the presence of iron, significantly increased in iron-starved cells. Thus, an increase in respiration may compensate for the drastic decrease of photosynthetic electron transport activity in MuD grown under iron starvation. Based on the similarity of the S. elongatus IdiC to the NuoE subunit of the NDH-1 complex in Escherichia coli, it is likely that IdiC has a function in the electron transport processes from NAD(P)H to the plastoquinone pool. This is in agreement with the up-regulation of IdiC in the late growth phase as well as under stress conditions when PS II is damaged. As absence or high reduction of the IdiC level would prevent or reduce the formation of functional NDH-1 complexes, under such conditions electron transport routes via alternative substrate dehydrogenases, donating electrons to the plastoquinone pool, can be assumed to be up-regulated. Springer Science+Business Media B.V., 2011 Synechococcus elongatus PCC 7942 nationallicence IdiC nationallicence Iron deficiency nationallicence Respiration nationallicence NDH-1 complex nationallicence IdiC : Iron deficiency-induced protein C nationallicence PS I : Photosystem I nationallicence PS II : Photosystem II nationallicence Chl a : Chlorophyll a nationallicence ICP-OES : Inductively coupled plasma optical emission spectrometry nationallicence IPTG : Isopropyl β-d-thiogalactoside nationallicence Pietsch Daniel Lehrstuhl für Molekulare Zellphysiologie, Fakultät für Biologie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany aut Bernát Gábor Lehrstuhl für Biochemie der Pflanzen, Ruhr-Universität Bochum, Universitätsstr. 150, 44780, Bochum, Germany aut Kahmann Uwe Lehrstuhl für Molekulare Zellphysiologie, Fakultät für Biologie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany aut Staiger Dorothee Lehrstuhl für Molekulare Zellphysiologie, Fakultät für Biologie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany aut Pistorius Elfriede Lehrstuhl für Molekulare Zellphysiologie, Fakultät für Biologie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany aut Michel Klaus-Peter Lehrstuhl für Molekulare Zellphysiologie, Fakultät für Biologie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany aut Photosynthesis Research Springer Netherlands 108/2-3(2011-09-01), 121-132 0166-8595 108:2-3<121 2011 108 11120 https://doi.org/10.1007/s11120-011-9661-1 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11120-011-9661-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Pietsch Daniel Lehrstuhl für Molekulare Zellphysiologie, Fakultät für Biologie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany aut NATIONALLICENCE 700 1- Bernát Gábor Lehrstuhl für Biochemie der Pflanzen, Ruhr-Universität Bochum, Universitätsstr. 150, 44780, Bochum, Germany aut NATIONALLICENCE 700 1- Kahmann Uwe Lehrstuhl für Molekulare Zellphysiologie, Fakultät für Biologie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany aut NATIONALLICENCE 700 1- Staiger Dorothee Lehrstuhl für Molekulare Zellphysiologie, Fakultät für Biologie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany aut NATIONALLICENCE 700 1- Pistorius Elfriede Lehrstuhl für Molekulare Zellphysiologie, Fakultät für Biologie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany aut NATIONALLICENCE 700 1- Michel Klaus-Peter Lehrstuhl für Molekulare Zellphysiologie, Fakultät für Biologie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany aut NATIONALLICENCE 773 0- Photosynthesis Research Springer Netherlands 108/2-3(2011-09-01), 121-132 0166-8595 108:2-3<121 2011 108 11120 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer