Comparative quantitative proteomics to investigate the remodeling of bioenergetic pathways under iron deficiency in Chlamydomonas reinhardtii.
The basic question addressed in this study is how energy metabolism is adjusted to cope with iron deficiency in Chlamydomonas reinhardtii. To investigate the impact of iron deficiency on bioenergetic pathways, comparative proteomics was combined with spectroscopic as well as voltametric oxygen measurements to assess protein dynamics linked to functional properties of respiratory and photosynthetic machineries. Although photosynthetic electron transfer is largely compromised under iron deficiency, our quantitative and spectroscopic data revealed that the functional antenna size of photosystem II (PSII) significantly increased. Concomitantly, stress-related chloroplast polypeptides, like 2-cys peroxiredoxin and a stress-inducible light-harvesting protein, LhcSR3, as well as a novel light-harvesting protein and several proteins of unknown function were induced under iron-deprivation. Respiratory oxygen consumption did not decrease and accordingly, polypeptides of respiratory complexes, harboring numerous iron-sulfur clusters, were only slightly diminished or even increased under low iron. Consequently, iron-deprivation induces a transition from photoheterotrophic to primarily heterotrophic metabolism, indicating that a hierarchy for iron allocations within organelles of a single cell exists that is closely linked with the metabolic state of the cell.
Naumann
Bianca
B
Institute of Plant Biochemistry and Biotechnology, University of Münster, Münster, Germany.
Busch
Andreas
A
Allmer
Jens
J
Ostendorf
Elisabeth
E
Zeller
Martin
M
Kirchhoff
Helmut
H
Hippler
Michael
M
D020418:Algal Proteins / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016825:Chlamydomonas reinhardtii / Q000235:genetics / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D004734:Energy Metabolism; D007501:Iron / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D045332:Photosystem II Protein Complex / Q000235:genetics / Q000378:metabolism; D040901:Proteomics / Q000379:methods; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013050:Spectrometry, Fluorescence; D053719:Tandem Mass Spectrometry
D020418:Algal Proteins; D017931:DNA Primers; D024101:Mitochondrial Proteins; D045332:Photosystem II Protein Complex; D015800:Protozoan Proteins; D002734:Chlorophyll; D007501:Iron